[3.7] Revert "bpo-31356: Add context manager to temporarily disable GC GH-5495 by miss-islington · Pull Request #5496 · python/cpython

@1st1 @miss-islington

…onGH-5495

This reverts commit 72a0d21.

The reverted commit had a few issues so it was unanimously decided
to undo it. See the bpo issue for details.
(cherry picked from commit 383b32f)

Co-authored-by: Yury Selivanov <yury@magic.io>