remove disabled mask load and store code

Things ran slower when we attempted to turn it on,
and we've already removed the analog in SkJumper_stages.cpp.

Change-Id: I61afa38990bf54d1bff2b1902f09a14df4e17da9
Reviewed-on: https://skia-review.googlesource.com/37080
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Mike Klein <mtklein@chromium.org>
1 file changed