Format all tests.

tests/language_strong/mixin_is_test.dart

Index: tests/language_strong/mixin_is_test.dart
diff --git a/tests/language_strong/mixin_is_test.dart b/tests/language_strong/mixin_is_test.dart
index 2e1cadaf2ebe10b53b95bf52782df4840d8577ad..89b5464aa5e16c0bf8439480a6418d47e24e0009 100644
--- a/tests/language_strong/mixin_is_test.dart
+++ b/tests/language_strong/mixin_is_test.dart
@@ -4,19 +4,23 @@
 
 import "package:expect/expect.dart";
 
-class S { }
-class M1 { }
-class M2 { }
+class S {}
+
+class M1 {}
+
+class M2 {}
 
 class C = S with M1;
 class D = S with M1, M2;
 class E = S with M2, M1;
-class F extends E { }
+
+class F extends E {}
 
 class C_ = S with M1;
 class D_ = S with M1, M2;
 class E_ = S with M2, M1;
-class F_ extends E_ { }
+
+class F_ extends E_ {}
 
 main() {
   var c = new C();