Due to both performance and reliability problems (crashes, incorrect rendering), I've disabled the usage of Vulkan on Android emulators. The android_engine_test (scenario app replacement), is exclusively using an Android emulator for testing.

While this allows it to easily run on presubmit, it does make us vunerable to the same crashes that currently plague the emulator Vulkan implementaiton.

ideally this could use a physical device, but perhaps that would not be easily possible on presubmit?

@zanderso / @matanlurey