RFR 8028141 intermittent test failure of LocalManagementTest

[roger riggs]

Please review this fix to improve the reliability of the 
jmxRemote/LocalManagementTest and CustomLauncherTest. The solution may 
apply to other tests that fail with ClassNotFound.

The tests did not include the jdk.testlibrary in the classpath when it 
spawns a new process. The failure mode is dependent on the order that 
tests had been run.

Also note that if a test depends on classes in the jdk.testlibrary it 
should include @build <classname> to ensure they are built in the 
@library directory

Webrev:
http://cr.openjdk.java.net/~rriggs/webrev-localmanagement-8028141/

Thanks, Roger