Specify COLRv1 gradient interpolation

Stage this behind a new SK_IGNORE_COLRV1_GRADIENT_COLORSPACE_FIX flag so
that users can be updated in an orderly fashion.

Bug: skia:40045100
Change-Id: I12b0b58f83476635b31b31deaa29e015bdf5010b
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/747671
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
2 files changed