Fix tests to reflect the current state (#526)

Author: srittau

tests/forward_refs_annassign.pyi

@@ -50,7 +50,7 @@ class Child(Parent): ...
 
 class MyClass:
     foo: int
-    bar = foo
+    bar = foo  # F821 undefined name 'foo'
 
 baz: MyClass
-eggs = baz
+eggs = baz  # F821 undefined name 'baz'

tests/vanilla_flake8_not_clean_forward_refs.pyi

@@ -3,6 +3,8 @@ from typing import TypeAlias, Union
 
 ManyStr: TypeAlias = list[EitherStr]  # F821 undefined name 'EitherStr'
 EitherStr: TypeAlias = Union[str, bytes]
-def function(accepts: EitherStr) -> None: ...
+# The following line reports "F821 undefined name 'EitherStr'" on Python 3.14+
+# but not on earlier versions.
+# def function(accepts: EitherStr) -> None: ...  # F821 undefined name 'EitherStr'
 
 del EitherStr  # private name, not exported