Consolidate nearly identical implementations and move them to
TurboAssembler, such that they can be reused for Liftoff.

R=neis@chromium.org

Bug: v8:6600
Change-Id: I197445404df033ac1a05f4aa88501263ae4b75f3
Reviewed-on: https://chromium-review.googlesource.com/1013561
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52634}