Convert NoMoreElementsException and EmptyQueueException to StateError.

lib/coreimpl/hash_map_set.dart

Index: lib/coreimpl/hash_map_set.dart
diff --git a/lib/coreimpl/hash_map_set.dart b/lib/coreimpl/hash_map_set.dart
index fe4a671557407e0ba049aea891f5f2522b34c4fa..d0c6bcba1b96159f9ae67a10bed0ae2fae14a827 100644
--- a/lib/coreimpl/hash_map_set.dart
+++ b/lib/coreimpl/hash_map_set.dart
@@ -419,7 +419,7 @@ class HashSetIterator<E> implements Iterator<E> {
 
   E next() {
     if (!hasNext) {
-      throw const NoMoreElementsException();
+      throw new StateError("No more elements");
     }
     E res = _entries[_nextValidIndex];
     _advance();