aaudio: make fewer assumptions about MMAP timestamp

Allow any amount of lateness.
This will allow the ClockModel to work with a wider range
of DSP behaviors. It should also handle timing jitter
caused by resampling in the DSP.
Use a drift value to stabilize the early and late ends of
the clock model window.

Test: run OboeTester Glitch Test
Bug: 123096058
Change-Id: Ic6e03d7878b26c4bf1d05708cff0ca2a771a9f80