Fix color gamut xform matrices in GPU code

Now that we're not storing them transposed, we can plumb them to the
shader column-major all the way, and then multiply colors on the right, as
it should be.

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2326093002

Review-Url: https://codereview.chromium.org/2326093002
2 files changed