Inconsistent rounding modes between `currentTimeUs` and
`bytesUntilNextSpeedChange` would cause `SpeedChangingAudioProcessor`
to miss calling `queueEndOfStream()` on `SonicAudioProcessor` on a speed
change, and thus the final output samples of that `SonicAudioProcessor`
"configuration" would be missed.
This change is also a partial revert of 971486f5f9, which fixed a hang
of `SpeedChangingAudioProcessor`, but introduced the dropped output
frames issue fixed in this CL (see b/372203420). To avoid reintroducing
the hang, we are now ignoring any mid-sample speed changes and will only
apply speed changes that are effective at a whole sample position.
PiperOrigin-RevId: 684824218
984b0bb31a