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

test/cctest/compiler/codegen-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_CODEGEN_TESTER_H_
 #define V8_CCTEST_COMPILER_CODEGEN_TESTER_H_
 
 #include "src/v8.h"
 
 #include "src/compiler/instruction-selector.h"
@@ skipping 12 matching lines @@
                                   public RawMachineAssembler {
  public:
   RawMachineAssemblerTester(MachineType p0 = kMachNone,
                             MachineType p1 = kMachNone,
                             MachineType p2 = kMachNone,
                             MachineType p3 = kMachNone,
                             MachineType p4 = kMachNone)
       : HandleAndZoneScope(),
         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)),
         RawMachineAssembler(
             main_isolate(), new (main_zone()) Graph(main_zone()),
-            MakeMachineSignature(
-                main_zone(), ReturnValueTraits<ReturnType>::Representation(),
-                p0, p1, p2, p3, p4),
+            MakeMachineSignature(main_zone(), MachineTypeForC<ReturnType>(), p0,
+                                 p1, p2, p3, p4),
             kMachPtr, InstructionSelector::SupportedMachineOperatorFlags()) {}
 
   void CheckNumber(double expected, Object* number) {
     CHECK(this->isolate()->factory()->NewNumber(expected)->SameValue(number));
   }
 
   void CheckString(const char* expected, Object* string) {
     CHECK(
         this->isolate()->factory()->InternalizeUtf8String(expected)->SameValue(
             string));
@@ skipping 284 matching lines @@
   } else {
     CHECK_EQ(x, y);
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CCTEST_COMPILER_CODEGEN_TESTER_H_