audio: Implement more accurate timing for the stub stream

Stub output stream is like a /dev/null audio device, however
for synchronous transfers it must block for the duration of
the audio chunk being transferred. Implement more accurate
accounting for the blocking time using the same approach as
employed by the remote submix stream implementation.

Bug: 356719263
Test: atest CtsNativeMediaAAudioTestCases
      on aosp_cf_x86_64_auto target
Change-Id: I137aed397246bcf2b5ef6789aa4d2d27ead64467