Format all tests.

tests/language/mixin_mixin4_test.dart

Index: tests/language/mixin_mixin4_test.dart
diff --git a/tests/language/mixin_mixin4_test.dart b/tests/language/mixin_mixin4_test.dart
index b527ef78407d187d02345977a8f13d88b6e62834..a982532f936bdce38b0fae36e14a783907d13f50 100644
--- a/tests/language/mixin_mixin4_test.dart
+++ b/tests/language/mixin_mixin4_test.dart
@@ -4,14 +4,16 @@
 
 import "package:expect/expect.dart";
 
-class I<T> { }
+class I<T> {}
 
-class J<T> { }
+class J<T> {}
 
-class S<T> { }
+class S<T> {}
 
 class M<T> {
-  t() { return T; }
+  t() {
+    return T;
+  }
 }
 
 class A<U, V> = Object with M<Map<U, V>> implements I<V>;