dart2js cps: Remove NonTailThrow.

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

Index: pkg/compiler/lib/src/cps_ir/cps_ir_builder.dart
diff --git a/pkg/compiler/lib/src/cps_ir/cps_ir_builder.dart b/pkg/compiler/lib/src/cps_ir/cps_ir_builder.dart
index 7117c80e7a4e597a117fa667f023780c3b90cd08..ca015802776c66db3a321916dbdbfa618ba81921 100644
--- a/pkg/compiler/lib/src/cps_ir/cps_ir_builder.dart
+++ b/pkg/compiler/lib/src/cps_ir/cps_ir_builder.dart
@@ -2098,7 +2098,10 @@ class IrBuilder {
 
   ir.Primitive buildNonTailThrow(ir.Primitive value) {
     assert(isOpen);
-    return addPrimitive(new ir.NonTailThrow(value));
+    ir.Parameter param = new ir.Parameter(null);
+    ir.Continuation cont = new ir.Continuation(<ir.Parameter>[param]);
+    add(new ir.LetCont(cont, new ir.Throw(value)));
+    return param;
   }
 
   void buildRethrow() {