Implement compile-time optimization for mod().

$genType mod($genType x, float y);
$genType mod($genType x, $genType y);
$genHType mod($genHType x, half y);
$genHType mod($genHType x, $genHType y);

Change-Id: I406eafbe824d7aa55012196521e6f10cac50ed19
Bug: skia:12034
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/412376
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
5 files changed