Consolidate TILEX_LOW_BITS/TILEY_LOW_BITS -> EXTRACT_LOW_BITS

R=reed@google.com

CQ_INCLUDE_TRYBOTS=skia.primary:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD

Change-Id: I5450d1ae3239c9d4e70502fc042222410ac77e72
Reviewed-on: https://skia-review.googlesource.com/6265
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Florin Malita <fmalita@chromium.org>
7 files changed