Remove the different length string types...

src/heap-inl.h

Index: src/heap-inl.h
===================================================================
--- src/heap-inl.h	(revision 3336)
+++ src/heap-inl.h	(working copy)
@@ -41,10 +41,10 @@
 
 Object* Heap::AllocateSymbol(Vector<const char> str,
                              int chars,
-                             uint32_t length_field) {
+                             uint32_t hash_field) {
   unibrow::Utf8InputBuffer<> buffer(str.start(),
                                     static_cast<unsigned>(str.length()));
-  return AllocateInternalSymbol(&buffer, chars, length_field);
+  return AllocateInternalSymbol(&buffer, chars, hash_field);
 }