Reenable ability to Dispose already Disposed Vector.

src/utils.h

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 324 matching lines @@
 
   void Truncate(int length) {
     ASSERT(length <= length_);
     length_ = length;
   }
 
   // Releases the array underlying this vector. Once disposed the
   // vector is empty.
   void Dispose() {
     DeleteArray(start_);
-    if (is_empty()) return;
     start_ = NULL;
     length_ = 0;
   }
 
   inline Vector<T> operator+(int offset) {
     ASSERT(offset < length_);
     return Vector<T>(start_ + offset, length_ - offset);
   }
 
   // Factory method for creating empty vectors.
@@ skipping 277 matching lines @@
 
   Dest dest;
   memcpy(&dest, &source, sizeof(dest));
   return dest;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_UTILS_H_