Rename instanceAttribSupport -> drawInstancedSupport

Change-Id: I7d8ff8597849f2b910928867842857e25a12b4b1
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/281582
Commit-Queue: Chris Dalton <csmartdalton@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
16 files changed