Add code to locate a plugin within a package

pkg/analysis_server/test/src/plugin/test_all.dart

Index: pkg/analysis_server/test/src/plugin/test_all.dart
diff --git a/pkg/analysis_server/test/src/plugin/test_all.dart b/pkg/analysis_server/test/src/plugin/test_all.dart
index c179a26af80e759ba91a786dcb88bb9b303d1bac..f4e0e38363b7fcb7e901e8ae788299ea8d624066 100644
--- a/pkg/analysis_server/test/src/plugin/test_all.dart
+++ b/pkg/analysis_server/test/src/plugin/test_all.dart
@@ -4,10 +4,12 @@
 
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
+import 'plugin_locator_test.dart' as plugin_locator_test;
 import 'result_collector_test.dart' as result_collector_test;
 
 main() {
   defineReflectiveSuite(() {
+    plugin_locator_test.main();
     result_collector_test.main();
   });
 }