Remove chmod +x for installation script for docker build. (#13772)

We've introduced chmod a+x for installation scripts in Dockerfiles.
but this turned out to be a bad idea. This was to accomodate
building on Azure Deveops which has filesystem that does not
keep executable bit. But the side-effect of it that the
layer of the script is invalidated when the permission is changed
to +x on linux. The problem is that the script has locally (on
checkout) different permissions depending on umask setting.

Therefore changing permissions for the image to +a is not best.

Instead we are running the scripts with bash directly, which does
not require changing of executable bit.
diff --git a/Dockerfile b/Dockerfile
index 813b001..623d80c 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -146,8 +146,7 @@
 COPY scripts/docker/install_mysql.sh /scripts/docker/install_mysql.sh
 COPY docker-context-files /docker-context-files
 # fix permission issue in Azure DevOps when running the script
-RUN chmod a+x /scripts/docker/install_mysql.sh
-RUN ./scripts/docker/install_mysql.sh dev
+RUN bash ./scripts/docker/install_mysql.sh dev
 
 ARG AIRFLOW_REPO=apache/airflow
 ENV AIRFLOW_REPO=${AIRFLOW_REPO}
@@ -194,8 +193,6 @@
 
 # Only copy install_airflow_from_latest_master.sh to not invalidate cache on other script changes
 COPY scripts/docker/install_airflow_from_latest_master.sh /scripts/docker/install_airflow_from_latest_master.sh
-# fix permission issue in Azure DevOps when running the script
-RUN chmod a+x /scripts/docker/install_airflow_from_latest_master.sh
 
 # By default we do not upgrade to latest dependencies
 ARG UPGRADE_TO_NEWER_DEPENDENCIES="false"
@@ -209,7 +206,7 @@
 # account for removed dependencies (we do not install them in the first place)
 RUN if [[ ${AIRFLOW_PRE_CACHED_PIP_PACKAGES} == "true" && \
           ${UPGRADE_TO_NEWER_DEPENDENCIES} == "false" ]]; then \
-        /scripts/docker/install_airflow_from_latest_master.sh; \
+        bash /scripts/docker/install_airflow_from_latest_master.sh; \
     fi
 
 # By default we install latest airflow from PyPI so we do not need to copy sources of Airflow
@@ -270,28 +267,24 @@
 
 # Copy all install scripts here
 COPY scripts/docker/install*.sh /scripts/docker/
-# fix permission issue in Azure DevOps when running the script
-RUN chmod a+x /scripts/docker/instal*.sh
 
 # hadolint ignore=SC2086, SC2010
 RUN if [[ ${INSTALL_FROM_PYPI} == "true" ]]; then \
-        /scripts/docker/install_airflow.sh; \
+        bash /scripts/docker/install_airflow.sh; \
     fi; \
     if [[ ${INSTALL_FROM_DOCKER_CONTEXT_FILES} == "true" ]]; then \
-        /scripts/docker/install_from_docker_context_files.sh; \
+        bash /scripts/docker/install_from_docker_context_files.sh; \
     fi; \
     if [[ -n "${ADDITIONAL_PYTHON_DEPS}" ]]; then \
-        /scripts/docker/install_additional_dependencies.sh; \
+        bash /scripts/docker/install_additional_dependencies.sh; \
     fi; \
     find /root/.local/ -name '*.pyc' -print0 | xargs -0 rm -r || true ; \
     find /root/.local/ -type d -name '__pycache__' -print0 | xargs -0 rm -r || true
 
 # Copy compile_www_assets.sh install scripts here
 COPY scripts/docker/compile_www_assets.sh /scripts/docker/compile_www_assets.sh
-# fix permission issue in Azure DevOps when running the script
-RUN chmod a+x /scripts/docker/compile_www_assets.sh
 
-RUN /scripts/docker/compile_www_assets.sh
+RUN bash /scripts/docker/compile_www_assets.sh
 
 # make sure that all directories and files in .local are also group accessible
 RUN find /root/.local -executable -print0 | xargs --null chmod g+x && \
diff --git a/Dockerfile.ci b/Dockerfile.ci
index c0ad778..b5ca211 100644
--- a/Dockerfile.ci
+++ b/Dockerfile.ci
@@ -107,9 +107,7 @@
 
 # Only copy install_mysql.sh to not invalidate cache on other script changes
 COPY scripts/docker/install_mysql.sh /scripts/docker/install_mysql.sh
-# fix permission issue in Azure DevOps when running the script
-RUN chmod a+x /scripts/docker/install_mysql.sh
-RUN /scripts/docker/install_mysql.sh dev
+RUN bash /scripts/docker/install_mysql.sh dev
 
 RUN adduser airflow \
     && echo "airflow ALL=(ALL) NOPASSWD: ALL" > /etc/sudoers.d/airflow \
@@ -216,7 +214,6 @@
 
 # Additional scripts for managing BATS addons
 COPY scripts/docker/load.bash /opt/bats/lib/
-RUN chmod a+x /opt/bats/lib/load.bash
 
 # Optimizing installation of Cassandra driver
 # Speeds up building the image - cassandra driver without CYTHON saves around 10 minutes
@@ -288,8 +285,6 @@
 
 # Only copy install_airflow_from_latest_master.sh to not invalidate cache on other script changes
 COPY scripts/docker/install_airflow_from_latest_master.sh /scripts/docker/install_airflow_from_latest_master.sh
-# fix permission issue in Azure DevOps when running the script
-RUN chmod a+x /scripts/docker/install_airflow_from_latest_master.sh
 
 ARG UPGRADE_TO_NEWER_DEPENDENCIES="false"
 ENV UPGRADE_TO_NEWER_DEPENDENCIES=${UPGRADE_TO_NEWER_DEPENDENCIES}
@@ -303,7 +298,7 @@
 # account for removed dependencies (we do not install them in the first place)
 RUN if [[ ${AIRFLOW_PRE_CACHED_PIP_PACKAGES} == "true" && \
           ${UPGRADE_TO_NEWER_DEPENDENCIES} == "false" ]]; then \
-        /scripts/docker/install_airflow_from_latest_master.sh; \
+        bash /scripts/docker/install_airflow_from_latest_master.sh; \
     fi
 
 # Generate random hex dump file so that we can determine whether it's faster to rebuild the image
@@ -344,8 +339,6 @@
 
 # Only copy install_airflow.sh to not invalidate cache on other script changes
 COPY scripts/docker/install_airflow.sh /scripts/docker/install_airflow.sh
-# fix permission issue in Azure DevOps when running the script
-RUN chmod a+x /scripts/docker/install_airflow.sh
 
 # The goal of this line is to install the dependencies from the most current setup.py from sources
 # This will be usually incremental small set of packages in CI optimized build, so it will be very fast
@@ -354,20 +347,18 @@
 # But in cron job we will install latest versions matching setup.py to see if there is no breaking change
 # and push the constraints if everything is successful
 RUN if [[ ${INSTALL_FROM_PYPI} == "true" ]]; then \
-        /scripts/docker/install_airflow.sh; \
+        bash /scripts/docker/install_airflow.sh; \
     fi
 
 # Only copy install_from_docker_context_files.sh to not invalidate cache on other script changes
 COPY scripts/docker/install_from_docker_context_files.sh /scripts/docker/install_from_docker_context_files.sh
-# fix permission issue in Azure DevOps when running the script
-RUN chmod a+x /scripts/docker/install_from_docker_context_files.sh
 
 # If wheel files are found in /docker-context-files during installation
 # they are also installed additionally to whatever is installed from Airflow.
 COPY docker-context-files/ /docker-context-files/
 
 RUN if [[ ${INSTALL_FROM_DOCKER_CONTEXT_FILES} == "true" ]]; then \
-        /scripts/docker/install_from_docker_context_files.sh; \
+        bash /scripts/docker/install_from_docker_context_files.sh; \
     fi
 
 # Copy all the www/ files we need to compile assets. Done as two separate COPY
@@ -375,8 +366,9 @@
 COPY airflow/www/webpack.config.js ${AIRFLOW_SOURCES}/airflow/www/
 COPY airflow/www/static ${AIRFLOW_SOURCES}/airflow/www/static/
 COPY airflow/www/compile_assets.sh ${AIRFLOW_SOURCES}/airflow/www/compile_assets.sh
+
 # Package JS/css for production
-RUN airflow/www/compile_assets.sh
+RUN bash airflow/www/compile_assets.sh
 
 COPY scripts/in_container/entrypoint_ci.sh /entrypoint
 RUN chmod a+x /entrypoint