Implement compile-time optimization for reflect().

$genType  reflect($genType  I, $genType  N);
$genHType reflect($genHType I, $genHType N);

Change-Id: I59889ad767829bf7e33838737d7b7f6d1cbc3ece
Bug: skia:12034
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/412777
Commit-Queue: John Stiles <johnstiles@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
5 files changed