AAudio: Avoid scaling capacity with sample rate

When the apps using AAudio explicitly set the capacity, AAudio should
try its best to respect this capacity set.

This includes streams with sample rate conversion.

This CL prescales capacity by (deviceSampleRate / sampleRate) so that
when the capacity is scaled by (sampleRate / deviceSampleRate), it
will work as intended.

Bug: 382715299
Bug: 382390990
Test: atest AAudioTests
Test: OboeTester Test Glitches
Flag: EXEMPT bugfix
Change-Id: I427aef8364bb50fe7858aedc27ed7a9834f0940c