context/test: Add flag to test runner helper

This will later be used to allow skipping tests.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2151>

src/tests/stage-view-tests.c

@@ -1356,5 +1356,6 @@ main (int argc, char *argv[])
 
   init_tests ();
 
-  return meta_context_test_run_tests (META_CONTEXT_TEST (context));
+  return meta_context_test_run_tests (META_CONTEXT_TEST (context),
+                                      META_TEST_RUN_FLAG_NONE);
 }