middle: reset loop labels while visiting closure

This should fix #31754 and follow-up #25343.  Before the latter, the
closure was visited twice in the context of the enclosing fn, which
made even a single closure with a loop label emit a warning.

With this change, the closure is still visited within the context
of the main fn (which is intended, since it is not a separate item)
but resets the found loop labels while being visited.

Fixes: #31754

0 files changed, 0 insertions, 0 deletions