Add `ivec` GLSL type aliases to runtime effects

Also add unit test of all GLSL type aliases.

Bug: skia:10679
Change-Id: I93e21621c11adfe3f114d0c55fb8043518e62696
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/395718
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
6 files changed