bpo-45279: avoid redundant _commit_removals self._pending_removals guard

[graingert]

https://bugs.python.org/issue45279

_commit_removals already checks if pending_removals is empty via pop()

cpython/Lib/_weakrefset.py

Lines 53 to 61 in 3f8b23f

	def _commit_removals(self):
	pop = self._pending_removals.pop
	discard = self.data.discard
	while True:
	try:
	item = pop()
	except IndexError:
	return
	discard(item)

[asvetlov]

I believe, the check exists for the sake of performance: condition check is much faster than function call in Python.
Now the gap is smaller than 10 years ago but still relatively big.

[github-actions]

This PR is stale because it has been open for 30 days with no activity.

[JelleZijlstra]

@graingert what do you think? I'd be inclined to close this as the change may hurt performance and there's little clear benefit, so we should default to keeping things as they are.