dart2js cps: More aggressive operator specialization.

tests/compiler/dart2js/cps_ir/expected/argument_refinement_19.js

Index: tests/compiler/dart2js/cps_ir/expected/argument_refinement_19.js
diff --git a/tests/compiler/dart2js/cps_ir/expected/argument_refinement_19.js b/tests/compiler/dart2js/cps_ir/expected/argument_refinement_19.js
index c614b758b3d9d1f81a696c609c6840aa3bddc76a..25d7396d98e9b934da4e8ab514b1631174e0ce6a 100644
--- a/tests/compiler/dart2js/cps_ir/expected/argument_refinement_19.js
+++ b/tests/compiler/dart2js/cps_ir/expected/argument_refinement_19.js
@@ -10,12 +10,12 @@
 // }
 
 function() {
-  var x = P.int_parse("1233", null, null), y = P.int_parse("1234", null, null), v0 = typeof y === "number";
-  P.print(J.$div$n(x, 2));
+  var x = P.int_parse("1233", null, null), y = P.int_parse("1234", null, null);
+  P.print(x / 2);
   P.print(true);
-  P.print(v0);
-  if (!v0)
-    throw H.wrapException(H.argumentErrorValue(y));
+  P.print(typeof y === "number");
+  if (typeof y !== "number")
+    return H.iae(y);
   P.print(x + y);
   P.print(true);
 }