add modulefinder.test (#13148)

Author: tungol

stdlib/@tests/stubtest_allowlists/common.txt

@@ -72,7 +72,6 @@ ctypes.ARRAY
 ctypes.SetPointerType
 ctypes.c_voidp
 ctypes.util.test
-modulefinder.test
 multiprocessing.managers.Server.accepter
 multiprocessing.managers.Server.create
 multiprocessing.managers.Server.debug_info

stdlib/modulefinder.pyi

@@ -64,3 +64,5 @@ class ModuleFinder:
     def any_missing(self) -> list[str]: ...  # undocumented
     def any_missing_maybe(self) -> tuple[list[str], list[str]]: ...  # undocumented
     def replace_paths_in_code(self, co: CodeType) -> CodeType: ...  # undocumented
+
+def test() -> ModuleFinder | None: ...  # undocumented