[turbofan] Refactor the InstructionSelector tests.

testing/gtest-type-names.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_TESTING_GTEST_TYPE_NAMES_H_
-#define V8_TESTING_GTEST_TYPE_NAMES_H_
-
-#include "include/v8stdint.h"
-#include "testing/gtest/include/gtest/gtest.h"
-
-namespace testing {
-namespace internal {
-
-#define GET_TYPE_NAME(type)         \
-  template <>                       \
-  std::string GetTypeName<type>() { \
-    return #type;                   \
-  }
-GET_TYPE_NAME(int8_t)
-GET_TYPE_NAME(uint8_t)
-GET_TYPE_NAME(int16_t)
-GET_TYPE_NAME(uint16_t)
-GET_TYPE_NAME(int32_t)
-GET_TYPE_NAME(uint32_t)
-GET_TYPE_NAME(int64_t)
-GET_TYPE_NAME(uint64_t)
-GET_TYPE_NAME(float)
-GET_TYPE_NAME(double)
-#undef GET_TYPE_NAME
-
-}  // namespace internal
-}  // namespace testing
-
-#endif  // V8_TESTING_GTEST_TYPE_NAMES_H_