CI: use multiple threads to run CMake tests

The step, which is responsible for running CMake tests on
CI is extended to use multiple threads. This speeds up the
execution.

It is achieved via 'CTEST_PARALLEL_LEVEL' environment variable.

Signed-off-by: Patryk Wrobel <183546751+pwrobeldev@users.noreply.github.com>

Author: pwrobeldev

.github/workflows/functional-tests.yml

@@ -450,6 +450,7 @@ jobs:
           sudo apt -y install ./dart_${DART_VERSION}-1_amd64.deb
       - name: Build and run functional tests
         run: |
+          export CTEST_PARALLEL_LEVEL=4
           export ANDROID_HOME=${HOME}/android-sdk-linux
           export PATH=${PATH}:${ANDROID_HOME}/tools:${ANDROID_HOME}/tools/bin:${ANDROID_HOME}/platform-tools:/usr/lib/dart/bin
           ./gradlew publishToMavenLocal