Remove sk_64_isS32 and sk_64_asS32

This is an API change. I assume that only Skia uses these routines.

Change-Id: Iefc98fa5c0b83eb4f52c478e345fd99121ecb254
Reviewed-on: https://skia-review.googlesource.com/129440
Reviewed-by: Herb Derby <herb@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
10 files changed