Run closed_world2_test using the normal compiler pipeline.

tests/compiler/dart2js/source_map_name_test.dart

Index: tests/compiler/dart2js/source_map_name_test.dart
diff --git a/tests/compiler/dart2js/source_map_name_test.dart b/tests/compiler/dart2js/source_map_name_test.dart
index f0e1ec4583849396fc4a972dc9eb02213a88b093..8a92238bc4898851a5be6188282d2e193483902f 100644
--- a/tests/compiler/dart2js/source_map_name_test.dart
+++ b/tests/compiler/dart2js/source_map_name_test.dart
@@ -82,17 +82,18 @@ main() {
     CompilationResult result =
         await runCompiler(memorySourceFiles: {'main.dart': SOURCE});
     Compiler compiler = result.compiler;
+    LibraryElement mainApp = compiler.mainApp;
 
     Element lookup(String name) {
       Element element;
       int dotPosition = name.indexOf('.');
       if (dotPosition != -1) {
         String clsName = name.substring(0, dotPosition);
-        ClassElement cls = compiler.mainApp.find(clsName);
+        ClassElement cls = mainApp.find(clsName);
         Expect.isNotNull(cls, "Class '$clsName' not found.");
         element = cls.localLookup(name.substring(dotPosition + 1));
       } else {
-        element = compiler.mainApp.find(name);
+        element = mainApp.find(name);
       }
       Expect.isNotNull(element, "Element '$name' not found.");
       return element;