[turbofan] Tester improvements; use CSignature and simplify ReturnValueTraits.

test/cctest/compiler/graph-builder-tester.h

 // 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.
 
 #ifndef V8_CCTEST_COMPILER_GRAPH_BUILDER_TESTER_H_
 #define V8_CCTEST_COMPILER_GRAPH_BUILDER_TESTER_H_
 
 #include "src/v8.h"
 #include "test/cctest/cctest.h"
 
@@ skipping 34 matching lines @@
                            public SimplifiedGraphBuilder {
  public:
   explicit GraphBuilderTester(MachineType p0 = kMachNone,
                               MachineType p1 = kMachNone,
                               MachineType p2 = kMachNone,
                               MachineType p3 = kMachNone,
                               MachineType p4 = kMachNone)
       : GraphAndBuilders(main_zone()),
         CallHelper<ReturnType>(
             main_isolate(),
-            MakeMachineSignature(
-                main_zone(), ReturnValueTraits<ReturnType>::Representation(),
-                p0, p1, p2, p3, p4)),
+            MakeMachineSignature(main_zone(), MachineTypeForC<ReturnType>(), p0,
+                                 p1, p2, p3, p4)),
         SimplifiedGraphBuilder(main_isolate(), main_graph_, &main_common_,
                                &main_machine_, &main_simplified_),
         parameters_(main_zone()->template NewArray<Node*>(parameter_count())) {
     Begin(static_cast<int>(parameter_count()));
     InitParameters();
   }
   virtual ~GraphBuilderTester() {}
 
   void GenerateCode() { Generate(); }
   Node* Parameter(size_t index) {
@@ skipping 50 matching lines @@
     }
     return builder.Build();
   }
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CCTEST_COMPILER_GRAPH_BUILDER_TESTER_H_