split com.oracle.graal.truffle.* projects into a separate graal-truffle.jar and added truffle.jar to the boot class path
made -XX:+UseGraalClassLoader the default (now that truffle.jar is on the boot class path)
don't allow blocking compilation requests to Graal if Graal itself is not yet initialized
removed direct use of Unsafe.getUnsafe() since graal.jar is no longer on boot class path and so reflection method of accessed Unsafe must be used