CI: use home directory workaround for tests too

I'm not entirely sure why this step is needed, but I'm guessing it's a
result of actions/runner#863 clashing with the Docker container we build
in[1]. The "build-utee-teec" job already does this; this commit just
copies it over to the "build-and-run-examples-in-OPTEE-repo" job.

Without the step, the container's preinstalled rustup fails to work
properly. We'll soon be using the preinstalled version of rustup if it's
present, so we need this fix to keep the job passing.

[1] https://hub.docker.com/r/teaclave/teaclave-trustzone-sdk-build
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 20191fc..a4f02ed 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -92,6 +92,11 @@
           mkdir -p ~/optee-qemuv8 && cd ~/optee-qemuv8 &&
           repo init -u https://github.com/OP-TEE/manifest.git -m qemu_v8.xml &&
           repo sync -j4 --no-clone-bundle
+      - name: Setting up $HOME
+        run: |
+          cp /root/.bashrc $HOME/.bashrc &&
+          ln -sf /root/.rustup ~/.rustup &&
+          ln -sf /root/.cargo ~/.cargo
       - name: Build images and run tests
         run: |
           apt update && apt install libslirp-dev -y