gh-65961: Do not rely solely on __cached__ (GH-97990)

Make sure `__spec__.cached` (at minimum) can be used.

Lib/inspect.py

@@ -281,30 +281,15 @@ def get_annotations(obj, *, globals=None, locals=None, eval_str=False):
 
 # ----------------------------------------------------------- type-checking
 def ismodule(object):
-    """Return true if the object is a module.
-
-    Module objects provide these attributes:
-        __cached__      pathname to byte compiled file
-        __doc__         documentation string
-        __file__        filename (missing for built-in modules)"""
+    """Return true if the object is a module."""
     return isinstance(object, types.ModuleType)
 
 def isclass(object):
-    """Return true if the object is a class.
-
-    Class objects provide these attributes:
-        __doc__         documentation string
-        __module__      name of module in which this class was defined"""
+    """Return true if the object is a class."""
     return isinstance(object, type)
 
 def ismethod(object):
-    """Return true if the object is an instance method.
-
-    Instance method objects provide these attributes:
-        __doc__         documentation string
-        __name__        name with which this method was defined
-        __func__        function object containing implementation of method
-        __self__        instance to which this method is bound"""
+    """Return true if the object is an instance method."""
     return isinstance(object, types.MethodType)
 
 def ismethoddescriptor(object):