When the input to F64x2PromoteLowF32x4 is a S128Load64Zero, we can skip
the load + promote, and promote directly with a memory operand. The
tricky bit here is that on systems that rely on OOB trap handling, the
load is not eliminatable, so we always visit the S128Load64Zero, even
though after instruction-selector pattern-matching, it is unused. We
mark it as defined to skip visiting it, only if we matched it.

Bug: v8:12189
Change-Id: I0a805a3fce65c56ec52082b3625e1712ea1ee7cf
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3154347Reviewed-by: Georg Neis <neis@chromium.org>
Reviewed-by: Deepti Gandluri <gdeepti@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/main@{#76917}