RFR(S): 8231288: "jhsdb jmap" test needed to reproduce issues that used to be reproduced by JShellHeapDumpTest

[Chris Plummer]

Hello,

Please review the following:

https://bugs.openjdk.java.net/browse/JDK-8231288
http://cr.openjdk.java.net/~cjplummer/8231288/webrev.00/index.html

There were a number of jmap issues that JShellHeapDumpTest.java used to 
reproduce that went away with the fixes for JDK-8228625 because these 
fixes bring the jshell process to an idle state. This new test gets rid 
of the Thread.sleep(2000) that JShellHeapDumpTest.java does, making it 
so the jshell process is still active during the jmap heap dump. The 
helps to reproduce 4 other jmap bugs for which there are open CRs 
already filed. This new test has to be problem listed as a results.

Note I left mention of JDK-8196969 out of the problemlist because a fix 
for it is about to be pushed by someone else, and I don't want either of 
us to have to deal with timing issues for which CR gets pushed first.

thanks,

Chris