fix Library*NegativeTests (and a couple Prefix ones by accident)

frog/lib/corelib_impl.dart

Index: frog/lib/corelib_impl.dart
diff --git a/frog/lib/corelib_impl.dart b/frog/lib/corelib_impl.dart
index e83331c325fcbd16f8a6463ab39e2161cd863314..2d41fd06c4590f20cc75b2d5fdb65020c0ff5253 100644
--- a/frog/lib/corelib_impl.dart
+++ b/frog/lib/corelib_impl.dart
@@ -1,4 +1,4 @@
-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
@@ -221,6 +221,19 @@ class ImmutableList<E> extends ListFactory<E> {
   String toString() => new List.from(this).toString();
 }
 
+
+LinkedHashMapImplementation _map(List itemsAndKeys) {
+  LinkedHashMapImplementation ret = new LinkedHashMapImplementation();
+  for (int i=0; i < itemsAndKeys.length;) {
+    ret[itemsAndKeys[i++]] = itemsAndKeys[i++];
+  }
+  return ret;
+}
+
+ImmutableMap _constMap(List itemsAndKeys) {
+  return new ImmutableMap(itemsAndKeys);
+}
+
 /** An immutable map. */
 class ImmutableMap<K, V> implements Map<K, V> {
   final Map<K, V> _internal;