Cover runtime core tests on CI (#311)

Summary: Pull Request resolved: #311

Differential Revision: D49215928

Author: huydhn

.github/workflows/_unittest.yml

@@ -24,7 +24,7 @@ jobs:
     with:
       runner: ${{ inputs.runner }}
       docker-image: ${{ inputs.docker-image }}
-      submodules: 'true'
+      submodules: 'recursive'
       ref: ${{ github.event_name == 'pull_request' && github.event.pull_request.head.sha || github.sha }}
       timeout: 60
       script: |
@@ -38,3 +38,5 @@ jobs:
         pip install .
         # Run pytest with coverage
         pytest --cov=./ --cov-report=xml
+        # Run gtest
+        buck2 test runtime/core/... runtime/platform/...