Implement more of the behavior of a plugin; refactor some API

pkg/analyzer_plugin/test/plugin/test_all.dart

Index: pkg/analyzer_plugin/test/plugin/test_all.dart
diff --git a/pkg/analyzer_plugin/test/test_all.dart b/pkg/analyzer_plugin/test/plugin/test_all.dart
similarity index 68%
copy from pkg/analyzer_plugin/test/test_all.dart
copy to pkg/analyzer_plugin/test/plugin/test_all.dart
index 9b9fa63049383174eb3c81797c98c48d28bdf89c..c727a3612c553bfa5208ca1dd63038f3c88573a1 100644
--- a/pkg/analyzer_plugin/test/test_all.dart
+++ b/pkg/analyzer_plugin/test/plugin/test_all.dart
@@ -4,12 +4,10 @@
 
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
-import 'src/test_all.dart' as src;
-import 'utilities/test_all.dart' as utilities;
+import 'plugin_test.dart' as plugin_test;
 
 main() {
   defineReflectiveSuite(() {
-    src.main();
-    utilities.main();
-  }, name: 'analyzer_plugin');
+    plugin_test.main();
+  }, name: 'plugin');
 }