Turn off SupportsFlexibleFloorAndRound for Arm64 due to a bug.

src/hydrogen-instructions.h

 // Copyright 2012 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_HYDROGEN_INSTRUCTIONS_H_
 #define V8_HYDROGEN_INSTRUCTIONS_H_
 
 #include <cstring>
 #include <iosfwd>
 
@@ skipping 2556 matching lines @@
   bool DataEquals(HValue* other) OVERRIDE {
     HUnaryMathOperation* b = HUnaryMathOperation::cast(other);
     return op_ == b->op();
   }
 
  private:
   // Indicates if we support a double (and int32) output for Math.floor and
   // Math.round.
   bool SupportsFlexibleFloorAndRound() const {
 #ifdef V8_TARGET_ARCH_ARM64
-    return true;
+    // TODO(rmcilroy): Re-enable this for Arm64 once http://crbug.com/476477 is
+    // fixed.
+    return false;
 #else
     return false;
 #endif
   }
   HUnaryMathOperation(HValue* context, HValue* value, BuiltinFunctionId op)
       : HTemplateInstruction<2>(HType::TaggedNumber()), op_(op) {
     SetOperandAt(0, context);
     SetOperandAt(1, value);
     switch (op) {
       case kMathFloor:
@@ skipping 5288 matching lines @@
 };
 
 
 
 #undef DECLARE_INSTRUCTION
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_HYDROGEN_INSTRUCTIONS_H_