Make direct calls to _nativeIndexedGetter in "get last" "get first" "get single" instead of calling…

tools/dom/templates/immutable_list_mixin.darttemplate

Index: tools/dom/templates/immutable_list_mixin.darttemplate
===================================================================
--- tools/dom/templates/immutable_list_mixin.darttemplate	(revision 27268)
+++ tools/dom/templates/immutable_list_mixin.darttemplate	(working copy)
@@ -17,8 +17,12 @@
 $if DART2JS
       return JS('$E', '#[0]', this);
 $else
+$if USE_NATIVE_INDEXED_GETTER
+      return $GETTER(0);
+$else
       return this[0];
 $endif
+$endif
     }
     throw new StateError("No elements");
   }
@@ -29,8 +33,12 @@
 $if DART2JS
       return JS('$E', '#[#]', this, len - 1);
 $else
+$if USE_NATIVE_INDEXED_GETTER
+      return $GETTER(len - 1);
+$else
       return this[len - 1];
 $endif
+$endif
     }
     throw new StateError("No elements");
   }
@@ -41,8 +49,12 @@
 $if DART2JS
       return JS('$E', '#[0]', this);
 $else
+$if USE_NATIVE_INDEXED_GETTER
+      return $GETTER(0);
+$else
       return this[0];
 $endif
+$endif
     }
     if (len == 0) throw new StateError("No elements");
     throw new StateError("More than one element");