Fail test jobs on test failures (#4869)

If the test job succeeds despite test failures there is no way to
retrigger them.

b/354062546

.github/actions/on_device_tests/action.yaml

@@ -83,7 +83,8 @@ runs:
           --gcs_result_path "${GCS_RESULTS_PATH}" || {
             echo "Finished running tests..."
             echo "The test session failed. See logs for details."
-            exit 0
+            # Fail the job so it's easy to retrigger.
+            exit 1
           }
         echo "Finished running tests..."
       shell: bash

.github/actions/on_host_tests/action.yaml

@@ -82,6 +82,8 @@ runs:
         echo "Finished running tests..."
         if [ -n "${failed_suites}" ]; then
           echo "Test suites failed:${failed_suites}"
+          # Fail the job so it's easy to retrigger.
+          exit 1
         fi
     - name: Archive Test Results
       if: success() || failure()