Test Performance improvement. Test Timeout Mitigation.

Existing test case nifi-framework-core/src/test/java/org/apache/nifi/controller/TestStandardFlowFileQueue.java uses a huge number of call to UUID.randomUUID() which is very slow in linux , unix environment if there is not much activity [ like mouse move etc.] .In addition to that UUID.randomUUID() depends on /dev/(u)random to get a random number, such system call costs IO and /dev/random is bandwidth/rate limited which again slows down overall performance.

Workaround is rngd daemon(ref: http://linux.die.net/man/8/rngd)