dart2js cps: Remove NonTailThrow.

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

Index: pkg/compiler/lib/src/cps_ir/type_propagation.dart
diff --git a/pkg/compiler/lib/src/cps_ir/type_propagation.dart b/pkg/compiler/lib/src/cps_ir/type_propagation.dart
index 60e9c4c185f60c70905403a260a5bc70aeb3a00b..b9b1629158d50f26fc15c3f55e16fad5fa7e1258 100644
--- a/pkg/compiler/lib/src/cps_ir/type_propagation.dart
+++ b/pkg/compiler/lib/src/cps_ir/type_propagation.dart
@@ -1954,10 +1954,6 @@ class TypePropagationVisitor implements Visitor {
   void visitUnreachable(Unreachable node) {
   }
 
-  void visitNonTailThrow(NonTailThrow node) {
-    internalError(null, 'found non-tail throw after they were eliminated');
-  }
-
   void visitBranch(Branch node) {
     IsTrue isTrue = node.condition;
     AbstractValue conditionCell = getValue(isTrue.value.definition);