Re-land "Format all multitests"

tests/language_strong/flatten_test.dart

Index: tests/language_strong/flatten_test.dart
diff --git a/tests/language_strong/flatten_test.dart b/tests/language_strong/flatten_test.dart
index ab2cc0679a88ae8b8cfa11ceec302c785432e4c4..618c0b6a89397c9bb7bcc9a101218df9f83439c9 100644
--- a/tests/language_strong/flatten_test.dart
+++ b/tests/language_strong/flatten_test.dart
@@ -20,7 +20,6 @@ class Divergent<T> implements Future<Divergent<Divergent<T>>> {
 }
 */
 
-
 test() async {
   // flatten(Derived<int>) = int
   int x = await new Derived<int>(); //# 01: runtime error
@@ -47,4 +46,4 @@ test() async {
 
 main() {
   test();
-}
+}