Renamed the various 'stage' shader functions to have the actual effect name

This is purely to make debugging easier, as the shaders now make more sense
to read.

Change-Id: Ie8e9b9d36112fda3ff997d088955de5a0e2c787a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/281017
Auto-Submit: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
4 files changed