Don't do folder existence checks when parsing pub list results.

pkg/analyzer/test/file_system/physical_resource_provider_test.dart

 // Copyright (c) 2014, 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.physical_file_system;
 
 import 'dart:async';
 import 'dart:io' as io;
 
 import 'package:analyzer/file_system/file_system.dart';
@@ skipping 275 matching lines @@
         });
 
         test('folder', () {
           new io.Directory(join(path, 'myFolder')).createSync();
           var child = folder.getChild('myFolder');
           expect(child, _isFolder);
           expect(child.exists, isTrue);
         });
       });
 
+      group('getChildAssumingFolder', () {
+        test('does not exist', () {
+          Folder child = folder.getChildAssumingFolder('no-such-resource');
+          expect(child, isNotNull);
+          expect(child.exists, isFalse);
+        });
+
+        test('file', () {
+          new io.File(join(path, 'myFile')).createSync();
+          Folder child = folder.getChildAssumingFolder('myFile');
+          expect(child, isNotNull);
+          expect(child.exists, isFalse);
+        });
+
+        test('folder', () {
+          new io.Directory(join(path, 'myFolder')).createSync();
+          Folder child = folder.getChildAssumingFolder('myFolder');
+          expect(child, isNotNull);
+          expect(child.exists, isTrue);
+        });
+      });
+
       test('getChildren', () {
         // create 2 files and 1 folder
         new io.File(join(path, 'a.txt')).createSync();
         new io.Directory(join(path, 'bFolder')).createSync();
         new io.File(join(path, 'c.txt')).createSync();
         // prepare 3 children
         List<Resource> children = folder.getChildren();
         expect(children, hasLength(3));
         children.sort((a, b) => a.shortName.compareTo(b.shortName));
         // check that each child exists
@@ skipping 42 matching lines @@
         expect(
             folder.canonicalizePath(join('.', 'baz')),
             equals(join(path, 'baz')));
         expect(
             folder.canonicalizePath(join(path2, '.', 'baz')),
             equals(join(path2, 'baz')));
       });
     });
   });
 }