Chagnge TThreadPoolServer in Java to use SynchronousQueue by default

Chagnge TThreadPoolServer in Java to use SynchronousQueue by default

Summary: Read the documentation on ThreadPoolExecutor. It's very confusing. Basically, what we want is a queue that always defers to the threadpool and will always create a new thread to do work. We never want the queue to take priority over the thread pool by default.

Reviewed By: dreiss

Test Plan: Run a Java Thrift server

git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@665419 13f79535-47bb-0310-9956-ffa450edef68