Prefer fullscreen clears on QC/Vulkan

Bug: skia:7396
Bug: skia:8430
Change-Id: Ia44dc162c4de71715d696e4d41d3356ef4db363b
Reviewed-on: https://skia-review.googlesource.com/c/160263
Commit-Queue: Chris Dalton <csmartdalton@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
1 file changed