[turbofan] Make MachineType a pair of enums.

src/compiler/js-builtin-reducer.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/js-builtin-reducer.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler/node-properties.h"
 #include "src/compiler/simplified-operator.h"
 #include "src/objects-inl.h"
@@ skipping 89 matching lines @@
   if (r.InputsMatchOne(Type::Number())) {
     // Math.max(a:number) -> a
     return Replace(r.left());
   }
   if (r.InputsMatchAll(Type::Integral32())) {
     // Math.max(a:int32, b:int32, ...)
     Node* value = r.GetJSCallInput(0);
     for (int i = 1; i < r.GetJSCallArity(); i++) {
       Node* const input = r.GetJSCallInput(i);
       value = graph()->NewNode(
-          common()->Select(kMachNone),
+          common()->Select(MachineRepresentation::kNone),
           graph()->NewNode(simplified()->NumberLessThan(), input, value), value,
           input);
     }
     return Replace(value);
   }
   return NoChange();
 }
 
 
 // ES6 draft 08-24-14, section 20.2.2.19.
@@ skipping 65 matching lines @@
 }
 
 
 SimplifiedOperatorBuilder* JSBuiltinReducer::simplified() const {
   return jsgraph()->simplified();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8