in a FOR loop, by removing the range(x,,)-like double
commas in this case, too, during program compilation.

Previous empty (missing) argument of RANGE was checked
by the terminating comma, but it can be a white space
after it, as in the following example:

FOR i IN RANGE COUNT 'letter' [ PRINT i ]

Change-Id: I67d0a4f089be06f30003d1b979b8f1801dbfa2e9
Reviewed-on: https://gerrit.libreoffice.org/71263
Tested-by: Jenkins
Reviewed-by: László Németh <nemeth@numbertext.org>