add unit tests for constructed types

tests/_tests/poly/polyfuns.cdi

+val aux : [ 'A* ] -> Int
+val f : T('A) -> Int
+val a : Int
+val b : Int

tests/test.list

@@ -24,3 +24,10 @@ Name: cql
 Group: cql
 Input: cql/TREE/*.cd cql/XMP/*.cd
 Cmd: ../cduce -c --verbose -I cql/TREE -I cql/XMP
+
+Name: poly
+Group: poly
+Input: poly/polyfuns.cd poly/polysyntax.cd
+Cmd: ../cduce -c --verbose -I poly
+
+