Functions with v128 in their signatures are always lowered to 4 word32.
So if a return happens to be have an input that is a f32x4 operation, we
get a register allocator error because it tries to fit a float into a
general register. To fix that we need to do some checks when lowering
kReturn, and for each input node, if we are returning a v128, and it is
to be lowered into 4 f32 nodes, we bitcast the floats to ints.

Bug: v8:10507
Change-Id: Iea2fdfc4057304ebf0898e6f7091124629c589f0
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2391331
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Reviewed-by: Bill Budge <bbudge@chromium.org>
Cr-Commit-Position: refs/heads/master@{#69705}