Removed byte/ubyte types from SkSL

These types had no tests, have never been used, and GLSL doesn't support
byte types.

Change-Id: Id423e3e4790be7f443acc88bce5497470c7d3fd4
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/404219
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
11 files changed