[turbofan] Remove dead code (related to the SeqStringChar lowering removal).

src/compiler/access-builder.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_ACCESS_BUILDER_H_
 #define V8_COMPILER_ACCESS_BUILDER_H_
 
 #include "src/compiler/simplified-operator.h"
 
 namespace v8 {
@@ skipping 85 matching lines @@
   // Provides access to SharedFunctionInfo::feedback_vector() field.
   static FieldAccess ForSharedFunctionInfoTypeFeedbackVector();
 
   // Provides access to FixedArray elements.
   static ElementAccess ForFixedArrayElement();
 
   // Provides access to Fixed{type}TypedArray and External{type}Array elements.
   static ElementAccess ForTypedArrayElement(ExternalArrayType type,
                                             bool is_external);
 
-  // Provides access to the characters of sequential strings.
-  static ElementAccess ForSeqStringChar(String::Encoding encoding);
-
   // ===========================================================================
   // Access to global per-isolate variables (based on external reference).
 
   // Provides access to the backing store of a StatsCounter.
   static FieldAccess ForStatsCounter();
 
   // ===========================================================================
   // Access to activation records on the stack (based on frame pointer).
 
   // Provides access to the next frame pointer in a stack frame.
   static FieldAccess ForFrameCallerFramePtr();
 
   // Provides access to the marker in a stack frame.
   static FieldAccess ForFrameMarker();
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(AccessBuilder);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_ACCESS_BUILDER_H_