Revert "Add fast-mode Uri class."

tests/compiler/dart2js/compiler_helper.dart

 // 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.
 
 library compiler_helper;
 
 import 'dart:async';
 import "package:expect/expect.dart";
 
 import 'package:compiler/src/elements/elements.dart'
@@ skipping 161 matching lines @@
       expectedErrors: expectedErrors,
       expectedWarnings: expectedWarnings);
   return compiler.run(uri).then((_) {
     lego.Element element = findElement(compiler, name);
     return check(compiler, element);
   });
 }
 
 Future compileSources(Map<String, String> sources,
                check(MockCompiler compiler)) {
-  Uri base = new Uri(scheme: 'source', path: '/');
+  Uri base = new Uri(scheme: 'source');
   Uri mainUri = base.resolve('main.dart');
   String mainCode = sources['main.dart'];
   Expect.isNotNull(mainCode, 'No source code found for "main.dart"');
   MockCompiler compiler = compilerFor(mainCode, mainUri);
   sources.forEach((String path, String code) {
     if (path == 'main.dart') return;
     compiler.registerSource(base.resolve(path), code);
   });
 
   return compiler.run(mainUri).then((_) {
@@ skipping 97 matching lines @@
     regexp = regexp.replaceAll(xRe, '(?:$anyIdentifier)');
     final spaceRe = new RegExp('\\s+');
     regexp = regexp.replaceAll(spaceRe, '(?:\\s*)');
     if (shouldMatch) {
       Expect.isTrue(new RegExp(regexp).hasMatch(generated));
     } else {
       Expect.isFalse(new RegExp(regexp).hasMatch(generated));
     }
   });
 }