Some tests in Google3 run on simulators that still don't have access to Metal. These tests cannot opt into Impeller till the simulators are updated. Per internal conversations, it is fine to accept updated goldens but not break these tests.

To unblock Slimpeller, there are two options, either keep the Skia backend around for these tests, or prepare a null backend that doesn't render anything and accept the updated goldens (if any). This issue tracks the latter solution as the team really wants to start shedding the legacy code ASAP.