RFR 8048193: [tests] Replace JPS and stdout based PID retrieval by Process.getPid()

[Jaroslav Bachorik]

Please, review the following test change.

Issue : https://bugs.openjdk.java.net/browse/JDK-8048193
Webrev: http://cr.openjdk.java.net/~jbachorik/8048193/webrev.00

Intricate log parsing in order to get an application PID is replaced 
with the new Process.getPid() API call. While doing this cleanup it also 
become obvious that it was unnecessary to start a socket server for each 
launched test application just in order to shut it down when the same 
functionality can be achieved through the usage of stdin/stdout provided 
by the Process instance.

Thanks,

-JB-