[test-extras.scm] upgrade options->sxml to parse   entities

The default xml->sxml parser handles only > < & '
" entities. We need to add handler for   as well.

gnucash/report/report-system/test/test-extras.scm

@@ -117,7 +117,8 @@
         (lambda ()
           (display render)))
       (catch 'parser-error
-        (lambda () (xml->sxml render))
+        (lambda () (xml->sxml render
+                              #:entities '((nbsp . "\xa0"))))
         (lambda (k . args)
           (format #t "*** XML error. see render output at ~a\n~a"
                   filename (gnc:html-render-options-changed options #t))