Loosen up SkSurface_Gpu::onIsCompatible a bit wrt FBO0-ness

Change-Id: Ie04f55c9fb94e4e4acd90b96cd7fb0d3c6b72e14
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/275041
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Peng Huang <penghuang@chromium.org>
2 files changed