SkVertices: Remove volatile/nonvolatile bit

No one was using this, and it added significant complexity to
GrDrawVerticesOp.

Bug: skia:9984
Change-Id: I23f38b3f5d853a8e531f13b6931cd57b5985a2c8
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/276407
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
7 files changed