Get rid of all the library tags.

lib/src/util/dart.dart

 // Copyright (c) 2015, 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.
 
-library test.util.dart;
-
 import 'dart:async';
 import 'dart:isolate';
 
 import 'package:analyzer/analyzer.dart';
 import 'package:source_span/source_span.dart';
 
 import 'string_literal_iterator.dart';
 
 /// Runs [code] in an isolate.
 ///
@@ skipping 52 matching lines @@
   }
 
   var start = contextRunes.offset;
   for (var spanRune in span.text.runes) {
     if (spanRune != contextRunes.current) return null;
     contextRunes.moveNext();
   }
 
   return file.span(start, contextRunes.offset);
 }