RFR(S) : 8210022 : remove jdk.testlibrary.ProcessThread, TestThread and XRun

[Igor Ignatyev]

http://cr.openjdk.java.net/~iignatyev//8210022/webrev.00/index.html
> 303 lines changed: 21 ins; 266 del; 16 mod; 

Hi all,

could you please review the testlibrary clean up which removes jdk.testlibrary.ProcessThread, TestThread and XRun classes and update all their users to use the same classes from jdk.test.lib.thread package.

JBS: https://bugs.openjdk.java.net/browse/JDK-8210022
webrev: http://cr.openjdk.java.net/~iignatyev//8210022/webrev.00/index.html
testing: changed tests + jdk-tier[1-3] (in progress)

Thanks,
-- Igor