Fix SkLocalMatrixShader::isAImage() to respect local matrix and image local matrix

Fixes cts tests.

b/37161109
b/37237678

Bug: skia:
Change-Id: Ida9ac5e4261e8a6b22e8cdc0e585e0e7929dbbfd
Reviewed-on: https://skia-review.googlesource.com/13249
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Mike Klein <mtklein@chromium.org>
4 files changed