[Impeller] Run Vulkan unit-tests by default.

[chinmaygarde]

Currently, running the unit-tests requires the --enable-impeller-vulkan GN option enabled. Now that we have landed the Vulkan backend and are iterating on it in tree, perhaps it is time to remove the need for this flag.

[chinmaygarde]

cc @iskakaushik WDYT?

[iskakaushik]

Agreed. Is there a way to enable some tests but not all to start with? I'll see if there is a way to do this incrementally for Vulkan.

[chinmaygarde]

@iskakaushik Are you still working on this? Feel free to unassign yourself if not. I can take a closer look at this too.

[iskakaushik]

Yup. flutter/buildroot#639 was a prerequisite for this. Seems like you rolled buildroot in flutter/engine#36901. I will continue working on this.

[chinmaygarde]

@iskakaushik Just catching up on old issues. Are there any blockers to doing this and removing the Vulkan opt-in on the host unit-tests?

[chinmaygarde]

This is fixed.