Avoid checking types of Callable when both type objects are pointing to the same reference. This is a small check which would speed up cases drastically such as recursive generics with unions, since the type is equal but Pytype holds the expanded union type and attempts to go in deep to figure out each individual type matches.

Avoid checking types of Callable when both type objects are pointing to the same reference. This is a small check which would speed up cases drastically such as recursive generics with unions, since the type is equal but Pytype holds the expanded union type and attempts to go in deep to figure out each individual type matches. #2337