Manual copy and paste of all code found in the namespace base. I didn't
change any of the implementation code. Pull in a new file for optimized
ARM implementation.

Added a list of adaptions made to document what is different from
chromium.

Change-Id: I88b4af45437506cf57755e48fdfc88027a5aed33
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2436610
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#70452}