Roll Observatory packages and add a roll script

packages/petitparser/test/all_tests.dart

+library petitparser.test.all_tests;
+
+import 'package:test/test.dart';
+
+import 'petitparser_test.dart' as core_test;
+import 'dart_test.dart' as dart_test;
+import 'debug_test.dart' as debug_test;
+import 'json_test.dart' as json_test;
+import 'lisp_test.dart' as lisp_test;
+import 'reflection_test.dart' as reflection_test;
+import 'smalltalk_test.dart' as smalltalk_test;
+import 'test_test.dart' as test_test;
+
+void main() {
+  group('PetitParser', core_test.main);
+  group('Dart', dart_test.main);
+  group('Debug', debug_test.main);
+  group('JSON', json_test.main);
+  group('Lisp', lisp_test.main);
+  group('Reflection', reflection_test.main);
+  group('Smalltalk', smalltalk_test.main);
+  group('Test', test_test.main);
+}