We had issues when combining host and guest presentation since certain configurations in guest presentation such as double buffering were very unoptimal for the host and would significantly affect the FPS. As a result of this, we've now made host presentation have its own presentation textures which are copied into from the guest at presentation time, allowing us to change parameters of the host presentation independently of the guest.
We've implemented the infrastructure for this which includes being able to create images from host GPU memory using VMA, an optimized linear texture sync and a method to do on-GPU texture-to-texture copies.
We've also moved to driving the V-Sync event using AChoreographer on its on thread in this PR, which more accurately encapsulates HOS behavior and allows games such as ARMS to boot as they depend on the V-Sync event being signalled even when the game isn't presenting.
An exceptional signal handler allows us to convert an OS signal into a C++ exception, this allows us to alleviate a lot of crashes that would otherwise occur from signals being thrown during execution of games and be able to handle them gracefully.
