Revert of update memset16/32 inlining heuristics (patchset #1 id:1 of https://coderev...

Revert of update memset16/32 inlining heuristics (patchset #1 id:1 of https://codereview.chromium.org/1357193002/ )

Reason for revert:
Who wants to land forever?

Original issue's description:
> update memset16/32 inlining heuristics
>
> I spent some time looking at perf.skia.org and it looks like we can do better.
>
> It is weird, weird, weird that on x86, we see three completely different behaviors:
>   - x86 Android: inlining better for small N, custom better for large N;
>   - Windows:     inlining better for large N, custom better for small N;
>   - other x86:   inlining generally better
>
> BUG=skia:4316,chromium:516426
>
> (Temporary, plan to revert.)
> TBR=reed@google.com
>
> Committed: https://skia.googlesource.com/skia/+/b68fa409fc00ce2f38e2a0fd6f9dc2379b372481

TBR=reed@google.com,jcgregorio@google.com,mtklein@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:4316,chromium:516426

Review URL: https://codereview.chromium.org/1358793002