If the input to a Switch happens to be something that we already know to
be zero-extended, then we don't need to emit a movl to zero-extend it.
This is a tiny optimization, but speeds up the Mono interpreter by 3%
because it's heavily dependent on switch dispatch speed.

Bug: v8:10606
Change-Id: I67ab6b6aeb93df4e420ea2afef41a2234d7da979
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2368195Reviewed-by: Zhi An Ng <zhin@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#69523}