unit tests: add comment (#36030)

* remove collection

* test

* back

* wtf it actually saves 10s?!

* ah that makes sense

* rm

* ?

* ugh

* qq

* bc

.github/workflows/selfdrive_tests.yaml

@@ -162,7 +162,8 @@ jobs:
       timeout-minutes: ${{ contains(runner.name, 'nsc') && ((steps.setup-step.outputs.duration < 18) && 1 || 2) || 20 }}
       run: |
         ${{ env.RUN }} "source selfdrive/test/setup_xvfb.sh && \
-                        $PYTEST --collect-only -m 'not slow' && \
+                        # Pre-compile Python bytecode so each pytest worker doesn't need to
+                        $PYTEST --collect-only -m 'not slow' -qq && \
                         MAX_EXAMPLES=1 $PYTEST -m 'not slow' && \
                         ./selfdrive/ui/tests/create_test_translations.sh && \
                         QT_QPA_PLATFORM=offscreen ./selfdrive/ui/tests/test_translations && \