Expand the compressed_textures GM

This CL adds testing for some edge cases in compressed texture handling

Bug: skia:9680
Change-Id: I4915f46bca9e2fb5c827a51152f28dc1e9d22942
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/266201
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
4 files changed