[turbofan] Drop obsolete unused JSStrictNotEqual operator.

src/compiler/js-type-hint-lowering.cc

 // Copyright 2017 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/compiler/js-type-hint-lowering.h"
 
 #include "src/compiler/js-graph.h"
 #include "src/compiler/operator-properties.h"
 #include "src/compiler/simplified-operator.h"
 #include "src/feedback-vector.h"
@@ skipping 173 matching lines @@
     : jsgraph_(jsgraph), feedback_vector_(feedback_vector) {}
 
 Reduction JSTypeHintLowering::ReduceBinaryOperation(const Operator* op,
                                                     Node* left, Node* right,
                                                     Node* effect, Node* control,
                                                     FeedbackSlot slot) {
   switch (op->opcode()) {
     case IrOpcode::kJSEqual:
     case IrOpcode::kJSStrictEqual:
     case IrOpcode::kJSNotEqual:
-    case IrOpcode::kJSStrictNotEqual:
       break;
     case IrOpcode::kJSLessThan:
     case IrOpcode::kJSGreaterThan:
     case IrOpcode::kJSLessThanOrEqual:
     case IrOpcode::kJSGreaterThanOrEqual: {
       JSSpeculativeBinopBuilder b(this, op, left, right, effect, control, slot);
       if (Node* node = b.TryBuildNumberCompare()) {
         return Reduction(node);
       }
       break;
@@ skipping 18 matching lines @@
     default:
       UNREACHABLE();
       break;
   }
   return Reduction();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8