GEODE-8899: Temporarily restore dunitParallelForks (#6335)

In my earlier commit to upgrade Gradle to v6.8.3, I inadvertently
removed the `-PdunitParallelForks` option from the build and test CI
scripts.

Some PRs do not yet include the Gradle upgrade. Without this option, the
Dockerized tests for those those PRs use only 8 test workers. Those
test tasks will likely time out.

The CI scripts must continue to specify `-PdunitParallelForks=<N>` until
all PRs include the Gradle upgrade.

Authored-by: Dale Emery <demery@vmware.com>
diff --git a/ci/scripts/execute_build.sh b/ci/scripts/execute_build.sh
index cd91a9a..1d8930d 100755
--- a/ci/scripts/execute_build.sh
+++ b/ci/scripts/execute_build.sh
@@ -77,13 +77,14 @@
 if [[ -n "${PARALLEL_DUNIT}" && "${PARALLEL_DUNIT}" == "true" ]]; then
   PARALLEL_DUNIT="-PparallelDunit -PdunitDockerUser=geode"
   if [ -n "${DUNIT_PARALLEL_FORKS}" ]; then
-    DUNIT_PARALLEL_FORKS="--max-workers=${DUNIT_PARALLEL_FORKS} -PtestMaxParallelForks=${DUNIT_PARALLEL_FORKS}"
+    DUNIT_PARALLEL_FORKS="--max-workers=${DUNIT_PARALLEL_FORKS} -PtestMaxParallelForks=${DUNIT_PARALLEL_FORKS} -PdunitParallelForks=${DUNIT_PARALLEL_FORKS}"
   fi
 else
   PARALLEL_DUNIT=""
   DUNIT_PARALLEL_FORKS=""
 fi
 
+
 # SET_JAVA_HOME="export JAVA_HOME=/usr/lib/jvm/java-${JAVA_BUILD_VERSION}-openjdk-amd64"
 SET_JAVA_HOME="export JAVA_HOME=/usr/lib/jvm/bellsoft-java${JAVA_BUILD_VERSION}-amd64"
 
diff --git a/ci/scripts/execute_tests.sh b/ci/scripts/execute_tests.sh
index 916cc30..e2cf912 100755
--- a/ci/scripts/execute_tests.sh
+++ b/ci/scripts/execute_tests.sh
@@ -64,7 +64,7 @@
 if [[ -n "${PARALLEL_DUNIT}" && "${PARALLEL_DUNIT}" == "true" ]]; then
   PARALLEL_DUNIT="-PparallelDunit -PdunitDockerUser=geode -PdunitDockerImage=\$(docker images --format '{{.Repository}}:{{.Tag}}')"
   if [ -n "${DUNIT_PARALLEL_FORKS}" ]; then
-    DUNIT_PARALLEL_FORKS="--max-workers=${DUNIT_PARALLEL_FORKS} -PtestMaxParallelForks=${DUNIT_PARALLEL_FORKS}"
+    DUNIT_PARALLEL_FORKS="--max-workers=${DUNIT_PARALLEL_FORKS} -PtestMaxParallelForks=${DUNIT_PARALLEL_FORKS} -PdunitParallelForks=${DUNIT_PARALLEL_FORKS}"
   fi
 else
   PARALLEL_DUNIT=""