Introduce some helper functions to implement NEON operations that were
performing unary operations or binary operations lane-wise.

Not everything uses these helpers yet, in particular pairwise
operations, or zip/transpose.

Bug: v8:11074
Change-Id: Ia7e5b13ae79cd166c47535139d92adb7f7a7c1ab
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2516301
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71067}