[turbofan] Add Int64(Add|Sub)WithOverflow support.

test/cctest/compiler/codegen-tester.h

Index: test/cctest/compiler/codegen-tester.h
diff --git a/test/cctest/compiler/codegen-tester.h b/test/cctest/compiler/codegen-tester.h
index 53a504077b7e641d6442a3a61f514fd669b32ecb..56e90c65b7eed5da0a0c49a1c962b77b2c8a5350 100644
--- a/test/cctest/compiler/codegen-tester.h
+++ b/test/cctest/compiler/codegen-tester.h
@@ -369,6 +369,16 @@ class Int32BinopTester : public BinopTester<int32_t, USE_RETURN_REGISTER> {
 };
 
 
+// A helper class for testing code sequences that take two int parameters and
+// return an int value.
+class Int64BinopTester : public BinopTester<int64_t, USE_RETURN_REGISTER> {
+ public:
+  explicit Int64BinopTester(RawMachineAssemblerTester<int32_t>* tester)
+      : BinopTester<int64_t, USE_RETURN_REGISTER>(tester,
+                                                  MachineType::Int64()) {}
+};
+
+
 // A helper class for testing code sequences that take two uint parameters and
 // return an uint value.
 class Uint32BinopTester : public BinopTester<uint32_t, USE_RETURN_REGISTER> {