[turbofan] Use CompareNilIC for abstract equality with null/undefined.

src/code-factory.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_CODE_FACTORY_H_
 #define V8_CODE_FACTORY_H_
 
 #include "src/allocation.h"
 #include "src/assembler.h"
 #include "src/codegen.h"
@@ skipping 38 matching lines @@
   static Callable StoreIC(Isolate* isolate, LanguageMode mode);
   static Callable StoreICInOptimizedCode(Isolate* isolate, LanguageMode mode,
                                          InlineCacheState initialization_state);
   static Callable KeyedStoreIC(Isolate* isolate, LanguageMode mode);
   static Callable KeyedStoreICInOptimizedCode(
       Isolate* isolate, LanguageMode mode,
       InlineCacheState initialization_state);
 
   static Callable CompareIC(Isolate* isolate, Token::Value op,
                             Strength strength);
+  static Callable CompareNilIC(Isolate* isolate, NilValue nil_value);
 
   static Callable BinaryOpIC(Isolate* isolate, Token::Value op,
                              Strength strength);
 
   // Code stubs. Add methods here as needed to reduce dependency on
   // code-stubs.h.
   static Callable InstanceOf(Isolate* isolate);
 
   static Callable ToBoolean(
       Isolate* isolate, ToBooleanStub::ResultMode mode,
@@ skipping 31 matching lines @@
 
   static Callable InterpreterPushArgsAndCall(Isolate* isolate);
   static Callable InterpreterPushArgsAndConstruct(Isolate* isolate);
   static Callable InterpreterCEntry(Isolate* isolate);
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CODE_FACTORY_H_