Improve compilation speed on a pathological case > 2x (7 sec -> 2.7 sec) by improving local lookups.

runtime/vm/object.cc

Index: runtime/vm/object.cc
===================================================================
--- runtime/vm/object.cc	(revision 17040)
+++ runtime/vm/object.cc	(working copy)
@@ -10180,17 +10180,6 @@
 };
 
 
-intptr_t String::Hash() const {
-  intptr_t result = Smi::Value(raw_ptr()->hash_);
-  if (result != 0) {
-    return result;
-  }
-  result = String::Hash(*this, 0, this->Length());
-  this->SetHash(result);
-  return result;
-}
-
-
 intptr_t String::Hash(const String& str, intptr_t begin_index, intptr_t len) {
   ASSERT(begin_index >= 0);
   ASSERT(len >= 0);
@@ -10286,7 +10275,7 @@
 
   const String& other_string = String::Cast(other);
   if (this->HasHash() && other_string.HasHash() &&
-      (this->Hash() != other_string.Hash())) {
+      (this->StringHash() != other_string.StringHash())) {
     return false;  // Both sides have a hash code and it does not match.
   }
   return Equals(other_string, 0, other_string.Length());