Reland x3 "Drawing YUVA images does not flatten for bicubic."

Fixes:

Workaround GL_ALPHA texture issue in GM.

Don't crash in GM on null image.

Snap both coords in 1D bicubic (restores old behavior).

This reverts commit 97c98f95962aa6d053bbbd69b97944ea158acb35.

Change-Id: I14bf0f8c6acf87cac0a13b9166fac73a2f3520b0
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/278862
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
6 files changed