Allow non-AA clip rects to be scissor only even on MSAA targets

This appears to fix the performance regressions seen on a number of webpage
SKPs for vkmsaa8 and glmsaa targets on devices that can't disable multisampling.

Bug: skia:10730
Change-Id: I2c10a78cfe864f987b7f17eb69eb2e1712ca0676
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/317772
Reviewed-by: Chris Dalton <csmartdalton@google.com>
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
2 files changed