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

test/cctest/compiler/test-run-machops.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 <cmath>
 #include <functional>
 #include <limits>
 
 #include "src/base/bits.h"
 #include "src/base/utils/random-number-generator.h"
@@ skipping 4394 matching lines @@
   CHECK_EQ(&inputs[kInputSize], m.Call());
   for (int i = 0; i < kInputSize; i++) {
     CHECK_EQ(i, inputs[i]);
     CHECK_EQ(kInputSize - i - 1, outputs[i]);
   }
 }
 
 
 TEST(RunSpillLotsOfThings) {
   static const int kInputSize = 1000;
-  RawMachineAssemblerTester<void> m;
+  RawMachineAssemblerTester<int32_t> m;
   Node* accs[kInputSize];
   int32_t outputs[kInputSize];
   Node* one = m.Int32Constant(1);
   Node* acc = one;
   for (int i = 0; i < kInputSize; i++) {
     acc = m.Int32Add(acc, one);
     accs[i] = acc;
   }
   for (int i = 0; i < kInputSize; i++) {
     m.StoreToPointer(&outputs[i], kMachInt32, accs[i]);
@@ skipping 716 matching lines @@
   m.Return(m.Int32Constant(0));
   for (size_t i = 0; i < arraysize(kValues); ++i) {
     input = kValues[i];
     CHECK_EQ(0, m.Call());
     double expected = round(kValues[i]);
     CHECK_EQ(expected, result);
   }
 }
 
 #endif  // V8_TURBOFAN_TARGET