[turbofan] Implemented the optional Float32RoundDown operator.

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/compiler/instruction-selector.h"
 #include "src/compiler/pipeline.h"
 #include "src/compiler/raw-machine-assembler.h"
@@ skipping 494 matching lines @@
   void Run(RawMachineAssemblerTester<int32_t>* m);
   void RunLeft(RawMachineAssemblerTester<int32_t>* m);
   void RunRight(RawMachineAssemblerTester<int32_t>* m);
 };
 
 // TODO(bmeurer): Drop this crap once we switch to GTest/Gmock.
 static inline void CheckFloatEq(volatile float x, volatile float y) {
   if (std::isnan(x)) {
     CHECK(std::isnan(y));
   } else {
-    CHECK(x == y);
+    CHECK_EQ(x, y);
   }
 }
 
 static inline void CheckDoubleEq(volatile double x, volatile double y) {
   if (std::isnan(x)) {
     CHECK(std::isnan(y));
   } else {
     CHECK_EQ(x, y);
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CCTEST_COMPILER_CODEGEN_TESTER_H_