Add --no-background-compilation to tests that expect to run code in optimized form

tests/language/equality_test.dart

 // Copyright (c) 2012, 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.
-// VMOptions=--optimization-counter-threshold=10 --no-use-osr
+// VMOptions=--optimization-counter-threshold=10 --no-use-osr --no-background-compilation
 
 import "package:expect/expect.dart";
 
 
 class A {
   bool _result;
   A(this._result);
   operator ==(x) { return _result; }
 }
 
@@ skipping 58 matching lines @@
     Expect.isFalse(boolEqualityNegativeB(true));
     Expect.isTrue(boolEqualityNegativeB(false));
   }
 
   // Deoptimize.
   Expect.isFalse(boolEqualityPositiveA(1));
   Expect.isTrue(boolEqualityNegativeA("hi"));
   Expect.isFalse(boolEqualityPositiveB(2.0));
   Expect.isTrue(boolEqualityNegativeB([]));
 }