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

tests/language/try_catch_optimized2_test.dart

 // Copyright (c) 2013, 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
+// VMOptions=--optimization-counter-threshold=10 --no-background-compilation
 
 import "package:expect/expect.dart";
 
 // Test allocation sinking with optimized try-catch.
 
 bar() {  // Should not be inlined.
   try {
   } finally { }
 }
 
 foo(a) {
   var r = 0;
   for (var i in a) {
     r += i;
   }
   try {
     bar();
   } finally {
   }
   return r;
 }
 
 main() {
   var a = [1,2,3];
   for (var i = 0; i < 20; i++) foo(a);
   Expect.equals(6, foo(a));
 }