Revert "cleanup unused incremental resolution"

pkg/front_end/test/fasta/bootstrap_test.dart

Index: pkg/front_end/test/fasta/bootstrap_test.dart
diff --git a/pkg/front_end/test/fasta/bootstrap_test.dart b/pkg/front_end/test/fasta/bootstrap_test.dart
index 3387b34fddf11f16c17d008694c68efeea8e4918..95887d86d4be44772b7062f1dd45d1096aecee97 100644
--- a/pkg/front_end/test/fasta/bootstrap_test.dart
+++ b/pkg/front_end/test/fasta/bootstrap_test.dart
@@ -6,6 +6,8 @@ import 'dart:async' show Future;
 
 import 'dart:io' show Directory, File, Platform;
 
+import 'dart:isolate' show Isolate;
+
 import 'package:async_helper/async_helper.dart' show asyncEnd, asyncStart;
 
 import 'package:front_end/src/fasta/testing/patched_sdk_location.dart'
@@ -24,6 +26,7 @@ Future main() async {
   Uri sourceCompiler =
       Uri.base.resolve("pkg/front_end/tool/_fasta/compile.dart");
   Uri outline = Uri.base.resolve("pkg/front_end/tool/_fasta/outline.dart");
+  Uri packages = await Isolate.packageConfig;
   Directory tmp = await Directory.systemTemp.createTemp("fasta_bootstrap");
   Uri compiledOnceOutput = tmp.uri.resolve("fasta1.dill");
   Uri compiledTwiceOutput = tmp.uri.resolve("fasta2.dill");