gh-152358: Fix hash() of annotationlib.ForwardRef with unhashable value

[tonghuaroot]

ForwardRef.__eq__ and ForwardRef.__hash__ already compare and hash the
unhashable __globals__ and __cell__ fields by identity, but __owner__ and
__extra_names__ were used directly. Because a forward reference can hold an
arbitrary, possibly unhashable, value -- a value embedded in an annotation, or
an unhashable owner -- hash() raised TypeError while __eq__ succeeded, a
data model invariant violation that also broke storing forward references in
sets and as dict keys.

This applies the same id()-based treatment to __owner__ and __extra_names__
in both __eq__ and __hash__, mirroring the __cell__ fix in gh-143831 and
making __hash__ total. Comparing these fields by identity is consistent with
the existing __globals__/__cell__ handling, and two forward references
derived from the same annotation share the same objects, so they still compare
equal.

• Issue: annotationlib.ForwardRef.__hash__ raises TypeError on an unhashable value #152358