Draft: native: Forcefully yield back to the kernel if our rttime is running out

RTKit requires mutter to set a hard rlimit on how long it's thread will use CPU before going back to the kernel. This limit is about 12 frames.

Unfortunately, amdgpu seems to have a bug at the moment where it will cause the thread to stall longer than that when the screen is locked.

Rather than let the display server get slayed, this commit adds a roundtrip through the kernel to reset the clock when things are stalled.

Closes #3037 (closed)