Removes the full Smi handler from LoadField, leaving just the offset.
All other handler-based decisions (inline vs out-of-line, tagged vs.
double) should be done at graph building time and as separate IR nodes.

Bug: v8:7700
Change-Id: I55ba49edba5ef5628d5f30fc6ba60c8774e2ef9c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3602510Reviewed-by: Victor Gomes <victorgomes@chromium.org>
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80120}