Support bilerp filtering for all ShaderModes in GrTextureEffect.

Support MIP map for all but kRepeat.

Update texel_subset_ GMs to exercise newly supported modes.

Also makes GrTextureEffect do shader wrap modes for rectangle/
external textures even when not subsetted.

Change-Id: Ie2d299106120b5c6cc40365e8f300cc426dd5489
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/268163
Reviewed-by: Michael Ludwig <michaelludwig@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
3 files changed