GrContext abandon: fail -> skip

It's hard to run the preAbandonGpuContext bots if we consider abandoned
to be a hard failure.

Actually, can you double check my suspicion that checking
ctx->abandoned() here might kind of make the whole bot moot?  If we
check ctx->abandoned() here before drawing any GpuGM's content, isn't
the bot just spinning through without ever attempting to draw anything?

Cq-Include-Trybots: skia.primary:Test-Ubuntu18-Clang-Golo-GPU-QuadroP400-x86_64-Release-All-PreAbandonGpuContext
Change-Id: Id545ce88faef3bab6150cb5229422ab48399f5b3
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/205594
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
2 files changed