RFR for JDK-8030057: speed up forceLogSnapshot and checkAnnotations

[Tristan Yan]

Hi Everyone

Please help to review the code change for bug JDK-8030057.


http://cr.openjdk.java.net/~tyan/JDK-8030057/webrev.00/ 
<http://cr.openjdk.java.net/%7Etyan/JDK-8030057/webrev.00/>
Description:

Performance improvement for two RMI tests

java/rmi/activation/Activatable/forceLogSnapshot

method waitAllStarted is using recursive sleep to poll 50 
restartedObject to be true, we can use modern CountDownLatch to 
implement blocking-time wait.

Also suggest shorten waiting time to 5 seconds.

java/rmi/activation/Activatable/checkAnnotations

We can subclass ByteArrayOutputStream which support notification when 
data was written. Also use two thread wait output string and error 
string to be not null

Thank you
Tristan