Track IR ordering of SelectionDAG nodes 3/4.

Remove the old IR ordering mechanism and switch to new one.  Fix unit
test failures.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@182704 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h

@@ -377,11 +377,6 @@ public:
 
   void CopyValueToVirtualRegister(const Value *V, unsigned Reg);
 
-  /// AssignOrderingToNode - Assign an ordering to the node. The order is gotten
-  /// from how the code appeared in the source. The ordering is used by the
-  /// scheduler to effectively turn off scheduling.
-  void AssignOrderingToNode(const SDNode *Node);
-
   void visit(const Instruction &I);
 
   void visit(unsigned Opcode, const User &I);