Fix environment in HOptimizedGraphBuilder::VisitCountOperation. Follow-up for r14584.

test/mjsunit/regress/regress-2671-1.js

Index: test/mjsunit/regress/regress-2671-1.js
diff --git a/test/mjsunit/regress/regress-2671.js b/test/mjsunit/regress/regress-2671-1.js
similarity index 97%
copy from test/mjsunit/regress/regress-2671.js
copy to test/mjsunit/regress/regress-2671-1.js
index 8da1b8f07f69c487fe9913e485c60f3e257e0986..042a501e5adb86cd7d868ec721edef8edde27274 100644
--- a/test/mjsunit/regress/regress-2671.js
+++ b/test/mjsunit/regress/regress-2671-1.js
@@ -33,8 +33,8 @@ function f() {
   a[20] = 0;
   y = 3;
   var i = 7 * (y + -0);
-  a[i] = 1/y;
-  assertFalse(isNaN(a[i]));
+  a[i]++;
+  assertTrue(isNaN(a[i]));
 }
 
 f();