Java and Ruby thread do enqueue/create-threads differently

[pitr-ch]

Ruby pools create threads first before putting work to queue, java threads put work first into queue until full then they create new threads.

This needs to be unified.
We also need to implement java.util.concurrent.SynchronousQueue for Ruby and provide option for its usage on Ruby and Java.

[pitr-ch]

We probably need to take code from http://gee.cs.oswego.edu/cgi-bin/viewcvs.cgi/jsr166/src/jdk8/java/util/concurrent/ThreadPoolExecutor.java?view=markup and modify it to match our needs.