Revert of Allow NEON on iOS. (patchset #3 id:40001 of https://codereview.chromium.org/1091823002/)

Reason for revert:
need to coordinate this with chrome gyps/gn

Original issue's description:
> Allow NEON on iOS.
>
> I have nanobench building and running (Color32_arm_neon) on my iPad.
>
> No public API changes.
> TBR=reed@google.com
>
> BUG=skia:
>
> Committed: https://skia.googlesource.com/skia/+/e5043b7ea5170a639367b67c986568907576be4b

TBR=caryclark@google.com,mtklein@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/1094843005
2 files changed