More tests updated to optimize code (Part 2).

tests/language/issue11087_vm_test.dart

Index: tests/language/issue11087_vm_test.dart
===================================================================
--- tests/language/issue11087_vm_test.dart	(revision 24922)
+++ tests/language/issue11087_vm_test.dart	(working copy)
@@ -5,6 +5,8 @@
 // Regression test for VM's IfConverted pass not keeping graph structure and
 // use lists in sync.
 
+// VMOptions=--optimization-counter-threshold=10
+
 class A {
   int x;
 }
@@ -16,6 +18,6 @@
 }
 
 main() {
-  for (var i = 0; i < 10000; i++) f();
+  for (var i = 0; i < 20; i++) f();
 }