In the codegen for shift operations, we update the temp s128 register
with the shift value, before shifting src with temp. Thus we really want
src to be a different register from temp.

I found this with some locally-ran fuzzing.

Bug: v8:10115
Change-Id: Ie492570c672f352f0e19aef2b8498c86ec4fdd98
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2107359Reviewed-by: Deepti Gandluri <gdeepti@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66756}