Add a case for kWasmS128 in Spill. We encounter this in the
wasm-trace-memory-liftoff test, but that test was skipped on ARM and
ARM64 due to insufficient implementation of Liftoff on those archs. But
with recent changes, they are now capable of running this particular
test, so we enable it.

Drive-by fix for incorrect size used in vld1 for filling S128 values.

Bug: v8:9909
Change-Id: I8addd06ba3c9a40364e432180cd5dbc48debca23
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2007901
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65904}