Revert of [es2015] Precompute the descriptive string for symbols.

src/objects-inl.h

 // Copyright 2012 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.
 //
 // Review notes:
 //
 // - The use of macros in these inline functions may seem superfluous
 // but it is absolutely needed to make sure gcc generates optimal
 // code. gcc is not happy when attempting to inline too deep.
 //
@@ skipping 3467 matching lines @@
   if ((one->IsInternalizedString() && two->IsInternalizedString()) ||
       one->IsSymbol() || two->IsSymbol()) {
     return false;
   }
   return String::SlowEquals(Handle<String>::cast(one),
                             Handle<String>::cast(two));
 }
 
 
 ACCESSORS(Symbol, name, Object, kNameOffset)
-ACCESSORS(Symbol, descriptive_string, String, kDescriptiveStringOffset)
 SMI_ACCESSORS(Symbol, flags, kFlagsOffset)
 BOOL_ACCESSORS(Symbol, flags, is_private, kPrivateBit)
 BOOL_ACCESSORS(Symbol, flags, is_well_known_symbol, kWellKnownSymbolBit)
 BOOL_ACCESSORS(Symbol, flags, is_public, kPublicBit)
 
 bool String::Equals(String* other) {
   if (other == this) return true;
   if (this->IsInternalizedString() && other->IsInternalizedString()) {
     return false;
   }
@@ skipping 4769 matching lines @@
 #undef WRITE_BYTE_FIELD
 #undef NOBARRIER_READ_BYTE_FIELD
 #undef NOBARRIER_WRITE_BYTE_FIELD
 
 }  // namespace internal
 }  // namespace v8
 
 #include "src/objects/object-macros-undef.h"
 
 #endif  // V8_OBJECTS_INL_H_