Add Java 9+ version of ConcurrentDirectDeque

The clustering code uses ConcurrentDirectDeque for its local scheduler implementation. While a portable implementation exists, a faster implementation that relies on sun.misc.Unsafe will be used when running with a compatible JVM.

Now that jboss-parent includes profiles for multi-release jars, we can add a fast implementation (ported from Undertow) that uses VarHandle that will work on all Java9+ JVMs.