Issue #18200: Update the stdlib (except tests) to use

ModuleNotFoundError.

Lib/importlib/__init__.py

@@ -14,7 +14,7 @@ import sys
 
 try:
     import _frozen_importlib as _bootstrap
-except ImportError:
+except ModuleNotFoundError:
     from . import _bootstrap
     _bootstrap._setup(sys, _imp)
 else:

Lib/importlib/abc.py

@@ -3,7 +3,7 @@ from . import _bootstrap
 from . import machinery
 try:
     import _frozen_importlib
-except ImportError as exc:
+except ModuleNotFoundError as exc:
     if exc.name != '_frozen_importlib':
         raise
     _frozen_importlib = None