adjust regression test for discussion 3359

- incorporate fix from 3a2d57db33 (commitcomment-187528793)
- mark as should panic rather than ignored, this ensures that the test will be updated should this get fixed

tests-pl/discussion3359.pl

@@ -1,4 +1,4 @@
-:- use_module(library(clpz)).
+:- use_module(library(dcgs)).
 :- use_module(library(tabling)).
 
 :- table expr//0.
@@ -8,4 +8,4 @@ expr --> expr, "+", expr.
 
 run :- phrase(expr, "1+1+1+1+1").
 
-:- initialization(run).
+:- initialization(run).