[turbofan] Add proper conversion operators for int32<->int64.

test/compiler-unittests/compiler-unittests.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_COMPILER_UNITTESTS_COMPILER_UNITTESTS_H_
 #define V8_COMPILER_UNITTESTS_COMPILER_UNITTESTS_H_
 
 #include "include/v8.h"
 #include "src/zone.h"
 #include "testing/gtest-support.h"
@@ skipping 55 matching lines @@
   static void TearDownTestCase();
 
  private:
   static v8::Isolate* isolate_;
   v8::Isolate::Scope isolate_scope_;
   v8::HandleScope handle_scope_;
   v8::Context::Scope context_scope_;
   Zone zone_;
 };
 
+
+template <typename T>
+class CompilerTestWithParam : public CompilerTest,
+                              public ::testing::WithParamInterface<T> {};
+
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_UNITTESTS_COMPILER_UNITTESTS_H_