Make some parser test helper methods non-static.

pkg/analyzer/test/dart/ast/visitor_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 analyzer.test.dart.ast.visitor_test;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:test/test.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
@@ skipping 22 matching lines @@
   return q() + 4;
   }
 }
 A f(var p) {
   if ((p as A).g) {
     return p;
   } else {
     return null;
   }
 }''';
-    CompilationUnit unit = ParserTestCase.parseCompilationUnit(source);
+    CompilationUnit unit = parseCompilationUnit(source);
     List<AstNode> nodes = new List<AstNode>();
     BreadthFirstVisitor<Object> visitor =
         new _BreadthFirstVisitorTestHelper(nodes);
     visitor.visitAllNodes(unit);
     expect(nodes, hasLength(59));
     EngineTestCase.assertInstanceOf(
         (obj) => obj is CompilationUnit, CompilationUnit, nodes[0]);
     EngineTestCase.assertInstanceOf(
         (obj) => obj is ClassDeclaration, ClassDeclaration, nodes[2]);
     EngineTestCase.assertInstanceOf(
@@ skipping 16 matching lines @@
   List<AstNode> nodes;
 
   _BreadthFirstVisitorTestHelper(this.nodes) : super();
 
   @override
   Object visitNode(AstNode node) {
     nodes.add(node);
     return super.visitNode(node);
   }
 }