The 64-bit instruction selectors check whether the input value to
a ChangeUint32ToUint64 node was produced by a node that sets the upper
32 bits to zero, and if so, they avoid emitting an extra instruction to
clear the upper bits. This change:

1. Extends that existing mechanism to also include phi values: if all of
   the inputs to a phi value guarantee that the upper 32 bits are zero,
   then the phi value does too.
2. Updates x64 to include non-negative int32 constants in the list of
   nodes that always clear the upper bits. I didn't add this to any
   other architecture because I'm less certain of how they resolve moves
   from constants.

This change improves the speed of the Mono interpreter on x64 by about
5%.

Bug: v8:10606
Change-Id: Ife8ce9c7330524e0b2fad836209a81180b4870e8
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2382509Reviewed-by: Bill Budge <bbudge@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Commit-Queue: Seth Brenith <seth.brenith@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#69706}