[turbofan] Add Symbol feedback to Equal/StrictEqual.

src/compiler/simplified-operator.h

 // Copyright 2014 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_COMPILER_SIMPLIFIED_OPERATOR_H_
 #define V8_COMPILER_SIMPLIFIED_OPERATOR_H_
 
 #include <iosfwd>
 
 #include "src/base/compiler-specific.h"
@@ skipping 396 matching lines @@
 
   const Operator* CheckIf();
   const Operator* CheckBounds();
   const Operator* CheckMaps(CheckMapsFlags, ZoneHandleSet<Map>);
 
   const Operator* CheckHeapObject();
   const Operator* CheckInternalizedString();
   const Operator* CheckNumber();
   const Operator* CheckSmi();
   const Operator* CheckString();
+  const Operator* CheckSymbol();
   const Operator* CheckReceiver();
 
   const Operator* CheckedInt32Add();
   const Operator* CheckedInt32Sub();
   const Operator* CheckedInt32Div();
   const Operator* CheckedInt32Mod();
   const Operator* CheckedUint32Div();
   const Operator* CheckedUint32Mod();
   const Operator* CheckedInt32Mul(CheckForMinusZeroMode);
   const Operator* CheckedInt32ToTaggedSigned();
@@ skipping 70 matching lines @@
   Zone* const zone_;
 
   DISALLOW_COPY_AND_ASSIGN(SimplifiedOperatorBuilder);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_SIMPLIFIED_OPERATOR_H_