Crash in callback on Legacy streams when device reroutes between calling obtainBuffer() and releaseBuffer()

[philburk]

We have discovered a bug in AudioTrack that was introduced in 2012.
It can cause an intermittent crash in a data callback due to accessing memory after it has been freed.

It is described in detail in this Tech Note:
https://github.com/google/oboe/wiki/CrashUAF_ObtainReleaseBuffer

It can be reproduced using this new "Routing Stress" test. #1760

[philburk]

OboeTester Routing Stress test should say fixed in UDC
It is broken in TM and earlier builds.
b/278788670 | P3 | Oboe Tester - Routing Stress - App stopped on Bramble
b/274815060 | P1 | Occasional crash in media framework Aaudio on Tangor

[philburk]

Message says "Fixed in SDK 34 (U)."