Format all multitests

tests/language_strong/conditional_property_assignment_test.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // Verify semantics of the ?. operator when it appears on the LHS of an
 // assignment.
 
 import "package:expect/expect.dart";
 import "conditional_access_helper.dart" as h;
 
@@ skipping 11 matching lines @@
   static int staticInt;
 }
 
 class D {
   E v;
   D(this.v);
   static E staticE;
 }
 
 class E {
-  G operator+(int i) => new I();
+  G operator +(int i) => new I();
 }
 
 class F {}
 
 class G extends E implements F {}
 
 class H {}
 
 class I extends G implements H {}
 
@@ skipping 48 matching lines @@
   { h.D.staticE = new h.E(); h.F f = (h.D?.staticE += h.nullC()); Expect.identical(h.D.staticE, f); } //# 33: static type warning
   { D.staticE = new E(); H h = (D?.staticE += 1); Expect.identical(D.staticE, h); } //# 34: static type warning
   { h.D.staticE = new h.E(); h.H hh = (h.D?.staticE += 1); Expect.identical(h.D.staticE, hh); } //# 35: static type warning
 
   // '?.' cannot be used to assign to toplevel properties in libraries imported
   // via prefix.
   h?.topLevelVar = null; //# 20: compile-time error
   h?.topLevelVar += null; //# 21: compile-time error
   h?.topLevelVar ??= null; //# 22: compile-time error
 }