[fix] handle IllegalStateException in file:list#2

fixes eXist-db#5028

The Java code of DirectoryList can throw an IllegalStateException
when a non-existent directory is supplied as its first argument.
This exception class is now handled in file:list#2.

extensions/modules/file/src/main/java/org/exist/xquery/modules/file/DirectoryList.java

@@ -172,7 +172,7 @@ public Sequence eval(final Sequence[] args, final Sequence contextSequence) thro
             builder.endElement();
 
             return (NodeValue) builder.getDocument().getDocumentElement();
-        } catch (final IOException e) {
+        } catch (final IOException | IllegalStateException e) {
             throw new XPathException(this, e.getMessage());
         } finally {
             context.popDocumentContext();