Format all tests.

tests/language_strong/mixin_extends_method_test.dart

Index: tests/language_strong/mixin_extends_method_test.dart
diff --git a/tests/language_strong/mixin_extends_method_test.dart b/tests/language_strong/mixin_extends_method_test.dart
index f80b16e1af1acd2562a11a4fa44880552e2b77fb..61efc2fa67cda55964d135b5b82fa7c10e1e9350 100644
--- a/tests/language_strong/mixin_extends_method_test.dart
+++ b/tests/language_strong/mixin_extends_method_test.dart
@@ -20,9 +20,11 @@ class M2 {
   fez() => "M2-fez";
 }
 
-class C extends S with M1 { }
-class D extends S with M1, M2 { }
-class E extends S with M2, M1 { }
+class C extends S with M1 {}
+
+class D extends S with M1, M2 {}
+
+class E extends S with M2, M1 {}
 
 class F extends E {
   fez() => "F-fez";