RFR(S) 8023988: Move local scheduling of nodes to the CFG creation and code motion phase (PhaseCFG)

[Niclas Adlertz]

Hi all, 

The class PhaseCFG is responsible for creating the CFG and doing the global code motion. This should also include local scheduling of nodes within blocks.
I've moved all code related to local scheduling of nodes from class Block to class PhaseCFG. Now class Block looks more like the container it should be, and the local scheduling methods are no longer accessible from outside class PhaseCFG.

WEBREV: cr.openjdk.java.net/~adlertz/JDK-8023988/webrev00/
JBS: https://bugs.openjdk.java.net/browse/JDK-8023988

Kind Regards,
Niclas Adlertz