[turbofan] Make MachineType a pair of enums.

test/unittests/compiler/control-flow-optimizer-unittest.cc

Index: test/unittests/compiler/control-flow-optimizer-unittest.cc
diff --git a/test/unittests/compiler/control-flow-optimizer-unittest.cc b/test/unittests/compiler/control-flow-optimizer-unittest.cc
index 444f5f5feeb38593d9857834ea2979967d81c9bd..a5a3c74be239ba441e4d39bdba342880fa4ab9f2 100644
--- a/test/unittests/compiler/control-flow-optimizer-unittest.cc
+++ b/test/unittests/compiler/control-flow-optimizer-unittest.cc
@@ -105,8 +105,8 @@ TEST_F(ControlFlowOptimizerTest, CloneBranch) {
   Node* control1 = graph()->NewNode(common()->IfTrue(), branch0);
   Node* control2 = graph()->NewNode(common()->IfFalse(), branch0);
   Node* merge0 = graph()->NewNode(common()->Merge(2), control1, control2);
-  Node* phi0 =
-      graph()->NewNode(common()->Phi(kRepBit, 2), cond1, cond2, merge0);
+  Node* phi0 = graph()->NewNode(common()->Phi(MachineRepresentation::kBit, 2),
+                                cond1, cond2, merge0);
   Node* branch = graph()->NewNode(common()->Branch(), phi0, merge0);
   Node* if_true = graph()->NewNode(common()->IfTrue(), branch);
   Node* if_false = graph()->NewNode(common()->IfFalse(), branch);