The use of AHBs for external texture interop when the surface-texture based fallback is in effect (for plugins that have not completed the go/impeller-plugin-migration transition) has caused emulator tests to not be wired up.

This is like similar to our issues with AHBs on emulators causing the use of those swapchains to be gated.

We need to either figure out how to reconcile the AHB testing situation on emulators or test on actual devices.