Don't use `LinkedList` in the core libraries anymore.

runtime/lib/regexp_patch.dart

Index: runtime/lib/regexp_patch.dart
diff --git a/runtime/lib/regexp_patch.dart b/runtime/lib/regexp_patch.dart
index 5a6514527594dd6984225e89d4da16e81df87243..1533836dc5bfc82fce674505c4e85217e1f2aacf 100644
--- a/runtime/lib/regexp_patch.dart
+++ b/runtime/lib/regexp_patch.dart
@@ -13,7 +13,7 @@ class RegExp {
     if (value == null) {
       if (_cache.length > _MAX_CACHE_SIZE) {
         _RegExpHashKey lastKey = _recentlyUsed.last;
-        lastKey.unlink();
+        _recentlyUsed.remove(lastKey);
         _cache.remove(lastKey);
       }
 
@@ -46,13 +46,13 @@ class RegExp {
   static const int _MAX_CACHE_SIZE = 256;
   static final Map<_RegExpHashKey, _RegExpHashValue> _cache =
       new HashMap<_RegExpHashKey, _RegExpHashValue>();
-  static final LinkedList<_RegExpHashKey> _recentlyUsed =
-      new LinkedList<_RegExpHashKey>();
+  static final internal.LinkedList<_RegExpHashKey> _recentlyUsed =
+      new internal.LinkedList<_RegExpHashKey>();
 }
 
 // Represents both a key in the regular expression cache as well as its
 // corresponding entry in the LRU list.
-class _RegExpHashKey extends LinkedListEntry<_RegExpHashKey> {
+class _RegExpHashKey extends internal.LinkedListEntry<_RegExpHashKey> {
   final String pattern;
   final bool multiLine;
   final bool caseSensitive;