dart2js cps: Combine integer type check with bounds check.

pkg/compiler/lib/src/cps_ir/update_refinements.dart

Index: pkg/compiler/lib/src/cps_ir/update_refinements.dart
diff --git a/pkg/compiler/lib/src/cps_ir/update_refinements.dart b/pkg/compiler/lib/src/cps_ir/update_refinements.dart
index 3500521ac01464102c55211ee7276f96059846b2..5ce47a2d150c1c1cb729a9d5a42b1cb3a1731e43 100644
--- a/pkg/compiler/lib/src/cps_ir/update_refinements.dart
+++ b/pkg/compiler/lib/src/cps_ir/update_refinements.dart
@@ -73,6 +73,14 @@ class UpdateRefinements extends TrampolineRecursiveVisitor implements Pass {
     });
   }
 
+  visitBoundsCheck(BoundsCheck node) {
+    super.visitBoundsCheck(node);
+    if (node.hasIntegerCheck &&
+        typeSystem.isDefinitelyInt(node.index.definition.type)) {
+      node.checks &= ~BoundsCheck.INTEGER;
+    }
+  }
+
   processReference(Reference ref) {
     refine(ref);
   }