[es6] Fix prototype chain walk for instanceof.

src/crankshaft/arm/lithium-codegen-arm.cc

 // 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.
 
 #include "src/crankshaft/arm/lithium-codegen-arm.h"
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/crankshaft/arm/lithium-gap-resolver-arm.h"
@@ skipping 2508 matching lines @@
   // Deoptimize if the object needs to be access checked.
   __ ldrb(object_instance_type,
           FieldMemOperand(object_map, Map::kBitFieldOffset));
   __ tst(object_instance_type, Operand(1 << Map::kIsAccessCheckNeeded));
   DeoptimizeIf(ne, instr, Deoptimizer::kAccessCheck);
   // Deoptimize for proxies.
   __ CompareInstanceType(object_map, object_instance_type, JS_PROXY_TYPE);
   DeoptimizeIf(eq, instr, Deoptimizer::kProxy);
 
   __ ldr(object_prototype, FieldMemOperand(object_map, Map::kPrototypeOffset));
+  __ CompareRoot(object_prototype, Heap::kNullValueRootIndex);
+  EmitFalseBranch(instr, eq);
   __ cmp(object_prototype, prototype);
   EmitTrueBranch(instr, eq);
-  __ CompareRoot(object_prototype, Heap::kNullValueRootIndex);
-  EmitFalseBranch(instr, eq);
   __ ldr(object_map, FieldMemOperand(object_prototype, HeapObject::kMapOffset));
   __ b(&loop);
 }
 
 
 void LCodeGen::DoCmpT(LCmpT* instr) {
   DCHECK(ToRegister(instr->context()).is(cp));
   Token::Value op = instr->op();
 
   Handle<Code> ic = CodeFactory::CompareIC(isolate(), op).code();
@@ skipping 3017 matching lines @@
   __ ldr(result, FieldMemOperand(scratch,
                                  FixedArray::kHeaderSize - kPointerSize));
   __ bind(deferred->exit());
   __ bind(&done);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8