CI: run process replay in parallel (#24646)

* CI in parallel

* cache key

.github/workflows/selfdrive_tests.yaml

@@ -333,7 +333,7 @@ jobs:
     - name: Run replay
       run: |
         ${{ env.RUN }} "scons -j$(nproc) && \
-                        FILEREADER_CACHE=1 CI=1 coverage run selfdrive/test/process_replay/test_processes.py && \
+                        FILEREADER_CACHE=1 CI=1 coverage run selfdrive/test/process_replay/test_processes.py -j$(nproc) && \
                         coverage xml"
     - name: Print diff
       if: always()
@@ -348,7 +348,7 @@ jobs:
       if: ${{ failure() && github.event_name == 'pull_request' && github.repository == 'commaai/openpilot' && env.AZURE_TOKEN != '' }}
       run: |
         ${{ env.RUN }} "scons -j$(nproc) && \
-                        CI=1 AZURE_TOKEN='$AZURE_TOKEN' python selfdrive/test/process_replay/test_processes.py --upload-only"
+                        CI=1 AZURE_TOKEN='$AZURE_TOKEN' python selfdrive/test/process_replay/test_processes.py -j$(nproc) --upload-only"
     - name: "Upload coverage to Codecov"
       uses: codecov/codecov-action@v2