In memory64, the index is a 64-bit value even on 32 bit. Thus the bounds
check needs to check explicitly that the high word is zero. The (pointer
sized) low word is then checked against the actual memory size.

R=manoskouk@chromium.org

Bug: v8:10949
Change-Id: I311664ccadaec44a6c88777a60b1a3b45b6c0642
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2617088
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#72016}