We no longer need unique register for src, since I64x2Abs
macro-assembler handles the case when dst == src (by using the scratch).
This is equivalent to calling the VisitRRSimd helper.

Bug: v8:11190
Change-Id: Ibabb6da970e983ca2c9326057a6dc43cc7b7c435
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2750725Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#73385}