Add @type_check_only to various typeshed-only procotols in stdlib (#14465)

Mark various typeshed-only protocols as `@type_check_only` in stdlib

stdlib/compileall.pyi

@@ -1,10 +1,11 @@
 import sys
 from _typeshed import StrPath
 from py_compile import PycInvalidationMode
-from typing import Any, Protocol
+from typing import Any, Protocol, type_check_only
 
 __all__ = ["compile_dir", "compile_file", "compile_path"]
 
+@type_check_only
 class _SupportsSearch(Protocol):
     def search(self, string: str, /) -> Any: ...