Add a test of summaries that uses strong mode.

pkg/analyzer/test/src/summary/test_all.dart

Index: pkg/analyzer/test/src/summary/test_all.dart
diff --git a/pkg/analyzer/test/src/summary/test_all.dart b/pkg/analyzer/test/src/summary/test_all.dart
index 3a3b7d967e556ba594c322b5939fdf1e544cfcb0..7b0524a4945bdba1a4d33babcbcf79621709cee7 100644
--- a/pkg/analyzer/test/src/summary/test_all.dart
+++ b/pkg/analyzer/test/src/summary/test_all.dart
@@ -12,6 +12,7 @@ import 'name_filter_test.dart' as name_filter_test;
 import 'prelinker_test.dart' as prelinker_test;
 import 'resynthesize_test.dart' as resynthesize_test;
 import 'summarize_ast_test.dart' as summarize_ast_test;
+import 'summarize_elements_strong_test.dart' as summarize_elements_strong_test;
 import 'summarize_elements_test.dart' as summarize_elements_test;
 
 /// Utility for manually running all tests.
@@ -23,6 +24,7 @@ main() {
     prelinker_test.main();
     resynthesize_test.main();
     summarize_ast_test.main();
+    summarize_elements_strong_test.main();
     summarize_elements_test.main();
   });
 }