bpo-41654: Fix compiler warning in MemoryError_dealloc() (GH-22387) (GH-24894)

Fix warning:

Objects\exceptions.c(2324,56): warning C4098:
'MemoryError_dealloc': 'void' function returning a value
(cherry picked from commit bbeb223e)

Co-authored-by: Victor Stinner <vstinner@python.org>

Co-authored-by: Victor Stinner <vstinner@python.org>