Fix another warning in pkg/testing.

pkg/testing/lib/src/analyze.dart

Index: pkg/testing/lib/src/analyze.dart
diff --git a/pkg/testing/lib/src/analyze.dart b/pkg/testing/lib/src/analyze.dart
index 7f053e2c6feca8d8387f8f9e4b2b6799292d061d..22bf758b9e27ccded34a7de02e24087040ea4fb2 100644
--- a/pkg/testing/lib/src/analyze.dart
+++ b/pkg/testing/lib/src/analyze.dart
@@ -158,9 +158,9 @@ Future<Null> analyzeUris(
   if (uris.isEmpty) return;
   String topLevel;
   try {
-    topLevel = Uri
-        .directory(await git("rev-parse", <String>["--show-toplevel"]))
-        .toFilePath();
+    topLevel =
+        new Uri.directory(await git("rev-parse", <String>["--show-toplevel"]))
+            .toFilePath();
   } catch (e) {
     topLevel = Uri.base.toFilePath(windows: false);
   }