Add check_mipmaps subtest to BackendAllocation test

This is setting up the test for SkPixmap-initialized backend texture testing

Change-Id: I667a0e6d622c9408d7fb42fc4b5792b0efa2ffb4
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/243736
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
1 file changed