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

pkg/analyzer/test/file_system/memory_file_system_test.dart

Index: pkg/analyzer/test/file_system/memory_file_system_test.dart
diff --git a/pkg/analyzer/test/file_system/memory_file_system_test.dart b/pkg/analyzer/test/file_system/memory_file_system_test.dart
index 2dd95de9dd419e478ad486ee7817758c45bba982..4b1dc37a839846308f3dd2929696fa475c8714ba 100644
--- a/pkg/analyzer/test/file_system/memory_file_system_test.dart
+++ b/pkg/analyzer/test/file_system/memory_file_system_test.dart
@@ -16,8 +16,8 @@ import 'package:watcher/watcher.dart';
 
 
 var _isFile = new isInstanceOf<File>();
-var _isFolder = new isInstanceOf<Folder>();
 var _isFileSystemException = new isInstanceOf<FileSystemException>();
+var _isFolder = new isInstanceOf<Folder>();
 
 
 main() {
@@ -377,6 +377,28 @@ main() {
         });
       });
 
+      group('getChildAssumingFolder', () {
+        test('does not exist', () {
+          Folder child = folder.getChildAssumingFolder('foldername');
+          expect(child, isNotNull);
+          expect(child.exists, isFalse);
+        });
+
+        test('file', () {
+          provider.newFile('/foo/bar/foldername', 'content');
+          Folder child = folder.getChildAssumingFolder('foldername');
+          expect(child, isNotNull);
+          expect(child.exists, isFalse);
+        });
+
+        test('folder', () {
+          provider.newFolder('/foo/bar/foldername');
+          Folder child = folder.getChildAssumingFolder('foldername');
+          expect(child, isNotNull);
+          expect(child.exists, isTrue);
+        });
+      });
+
       test('getChildren', () {
         provider.newFile('/foo/bar/a.txt', 'aaa');
         provider.newFolder('/foo/bar/bFolder');