Add nanobench test for a Graphite 'small' SkSL shader.

Just like Ganesh, I've taken the fragment shader used by
GM_lcdtext for our "small" benchmark.

Change-Id: I03041649d147afe6892c6f89d8d4fe623ad0a164
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/743236
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
1 file changed