Remove GrDrawAtlasOp

The base device turns drawAtlas into drawVertices, which ends
up being *faster* (in my tests) than our specialized code.

It's certainly possible to write a custom version that's better,
but for now, it seems better to just do this.

Bug: skia:
Change-Id: I247f0c0a24fb21c8206f4e3ea9fecac85679ba73
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/203163
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
10 files changed