Revert of [turbofan] Speculatively optimize string character access.

src/isolate-inl.h

 // Copyright 2015 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_ISOLATE_INL_H_
 #define V8_ISOLATE_INL_H_
 
 #include "src/isolate.h"
 #include "src/objects-inl.h"
 
@@ skipping 115 matching lines @@
   // All that could be checked reliably is that
   // Array.prototype.constructor == Array. Given that limitation, no check is
   // done here. In place, there are mjsunit tests harmony/array-species* which
   // ensure that behavior is correct in various invalid protector cases.
 
   Cell* species_cell = heap()->species_protector();
   return species_cell->value()->IsSmi() &&
          Smi::cast(species_cell->value())->value() == kProtectorValid;
 }
 
-bool Isolate::IsStringBoundsCheckIntact() {
-  Cell* string_bounds_check_cell = heap()->string_bounds_check_protector();
-  return string_bounds_check_cell->value() == Smi::FromInt(kProtectorValid);
-}
-
 bool Isolate::IsStringLengthOverflowIntact() {
   PropertyCell* string_length_cell = heap()->string_length_protector();
   return string_length_cell->value() == Smi::FromInt(kProtectorValid);
 }
 
 bool Isolate::IsFastArrayIterationIntact() {
   Cell* fast_iteration_cell = heap()->fast_array_iteration_protector();
   return fast_iteration_cell->value() == Smi::FromInt(kProtectorValid);
 }
 
 bool Isolate::IsArrayBufferNeuteringIntact() {
   PropertyCell* buffer_neutering = heap()->array_buffer_neutering_protector();
   return buffer_neutering->value() == Smi::FromInt(kProtectorValid);
 }
 
 bool Isolate::IsArrayIteratorLookupChainIntact() {
   PropertyCell* array_iterator_cell = heap()->array_iterator_protector();
   return array_iterator_cell->value() == Smi::FromInt(kProtectorValid);
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_ISOLATE_INL_H_