Revert "Revert "Reland "asyncRescaleAndRead supports unpremul results on GPU"""

This reverts commit 7f296c421e2c9b38f2348cf152748b0e00f3f6aa.

Bug: skia:11019
Change-Id: Ia6aa029abc0cf6a3ccd5467e67e5faa2c0239955
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/353616
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
12 files changed