[misc] CI hygiene: enforce __main__ entry, drop silent-skipped tests, fix rerun-test protoc (#23305)

test/registered/debug_utils/source_patcher/test_code_patcher.py

@@ -254,3 +254,9 @@ class TestCodePatcher:
                 raise RuntimeError("test error")
 
         assert obj.greet("world") == "hello world"
+
+
+if __name__ == "__main__":
+    import sys
+
+    sys.exit(pytest.main([__file__, "-v"]))