Maintain the invariant that the pattern string in an atom regexp is always ...

src/handles.cc

Index: src/handles.cc
===================================================================
--- src/handles.cc	(revision 5888)
+++ src/handles.cc	(working copy)
@@ -224,13 +224,7 @@
 
 
 Handle<String> FlattenGetString(Handle<String> string) {
-  Handle<String> result;
-  CALL_AND_RETRY(string->TryFlatten(),
-                 { result = Handle<String>(String::cast(__object__));
-                   break; },
-                 return Handle<String>());
-  ASSERT(string->IsFlat());
-  return result;
+  CALL_HEAP_FUNCTION(string->TryFlatten(), String);
 }