SoundPool: Avoid busy waiting during stream restart

A stream on the restart queue can cause the StreamManager to
busy-wait.  This was introduced by a fix
commit ba04dbe7732bc2d016bf81c81bd349d931de63f2.

Test: Verbose log on StreamManager.cpp, run SoundPool CTS tests.
Bug: 182923919
Merged-In: Iae794bc957869426a4e1e27cd3c088aa9dd83208
Change-Id: Iae794bc957869426a4e1e27cd3c088aa9dd83208
1 file changed