Revert "Removed made-up kSBGRA pixel config."

This reverts commit ff95f6ca9dbf3d5a7155a38c0a9e4a27edbfaaed.

Reason for revert: Broke command buffer GLBackendAllocationTest??

Original change's description:
> Removed made-up kSBGRA pixel config.
> 
> We made up this pixel config and don't actually use it ourselves so lets
> kill it for simplicity.
> 
> Change-Id: I6ae1c78fe7ada336a2411d295e8836dfeecb2d5c
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/223979
> Reviewed-by: Robert Phillips <robertphillips@google.com>
> Commit-Queue: Greg Daniel <egdaniel@google.com>

TBR=egdaniel@google.com,robertphillips@google.com,brianosman@google.com

Change-Id: I62e954495a702c7ad050719d8a1d6c4abcea3f60
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/223990
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
19 files changed