[8u] RFR 8156169: Some sound tests rarely hangs because of incorrect synchronization

[Zhengyu Gu]

I would like to backport this patch, as Oracle 8u271 parity.

The original patch does not apply cleanly. Other than file path changes, 
there are a few copyright line conflicts.

One code conflict is in 
src/share/classes/javax/sound/midi/Sequence.java's getTracks() method. 
It appears 8u and 9u have different implementations.

Original bug: https://bugs.openjdk.java.net/browse/JDK-8156169
Original patch: http://hg.openjdk.java.net/jdk9/jdk9/jdk/rev/3dc009028cab


8u Webrev: http://cr.openjdk.java.net/~zgu/JDK-8156169-8u/webrev.00/

Test:
   javax/sound


Thanks,

-Zhengyu