[es6] Fix prototype chain walk for instanceof.

src/crankshaft/x87/lithium-codegen-x87.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.
 
 #if V8_TARGET_ARCH_X87
 
 #include "src/crankshaft/x87/lithium-codegen-x87.h"
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 2585 matching lines @@
 
   // Deoptimize if the object needs to be access checked.
   __ test_b(FieldOperand(object_map, Map::kBitFieldOffset),
             Immediate(1 << Map::kIsAccessCheckNeeded));
   DeoptimizeIf(not_zero, instr, Deoptimizer::kAccessCheck);
   // Deoptimize for proxies.
   __ CmpInstanceType(object_map, JS_PROXY_TYPE);
   DeoptimizeIf(equal, instr, Deoptimizer::kProxy);
 
   __ mov(object_prototype, FieldOperand(object_map, Map::kPrototypeOffset));
+  __ cmp(object_prototype, factory()->null_value());
+  EmitFalseBranch(instr, equal);
   __ cmp(object_prototype, prototype);
   EmitTrueBranch(instr, equal);
-  __ cmp(object_prototype, factory()->null_value());
-  EmitFalseBranch(instr, equal);
   __ mov(object_map, FieldOperand(object_prototype, HeapObject::kMapOffset));
   __ jmp(&loop);
 }
 
 
 void LCodeGen::DoCmpT(LCmpT* instr) {
   Token::Value op = instr->op();
 
   Handle<Code> ic = CodeFactory::CompareIC(isolate(), op).code();
   CallCode(ic, RelocInfo::CODE_TARGET, instr);
@@ skipping 3247 matching lines @@
   __ bind(deferred->exit());
   __ bind(&done);
 }
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X87