Make EXI use CoreTiming events like everything else instead of having its own special check.

Microphone is probably wrong/mistimed because it doesn't take into
account cycles late, but that's not a new issue here.

I'm too tired to test any device other than memory card.

This is hopefully a slight performance win.

I still have no idea what the root cause of the sound issue is.  It doesn't really make sense that calling UpdateInterrupts would 'batch' anything, as the original PR submitter suggested, if the same number of calls are being made, and there are no off-thread shenanigans with memory cards.  In fact, in lieu of such shenanigans, it's hard to imagine why a computer's CPU speed would affect *anything*, and of course sound playback has no direct relationship to EXI.  Perhaps... more calls to UpdateInterrupts in inner loops => slower computation => GPU thread finishes too early?  Might be worth testing in deterministic or single-core mode.  Anyway, if that's the issue, this should at least hide the symptom, as UpdateInterrupts is only called when necessary.