[turbofan] Drop obsolete unused JSStrictNotEqual operator.

src/builtins/builtins-number.cc

 // Copyright 2016 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/builtins/builtins-utils.h"
 #include "src/builtins/builtins.h"
 #include "src/code-factory.h"
 #include "src/code-stub-assembler.h"
 #include "src/conversions.h"
 #include "src/counters.h"
@@ skipping 1585 matching lines @@
   Node* context = Parameter(2);
 
   Return(Equal(kNegateResult, lhs, rhs, context));
 }
 
 TF_BUILTIN(StrictEqual, CodeStubAssembler) {
   Node* lhs = Parameter(0);
   Node* rhs = Parameter(1);
   Node* context = Parameter(2);
 
-  Return(StrictEqual(kDontNegateResult, lhs, rhs, context));
-}
-
-TF_BUILTIN(StrictNotEqual, CodeStubAssembler) {
-  Node* lhs = Parameter(0);
-  Node* rhs = Parameter(1);
-  Node* context = Parameter(2);
-
-  Return(StrictEqual(kNegateResult, lhs, rhs, context));
+  Return(StrictEqual(lhs, rhs, context));
 }
 
 }  // namespace internal
 }  // namespace v8