Bug #21111. Reviewed by John Darrington.

* command/input-program.sh: New test.

* command/do-if.sh: New tests.

* data-list.c (data_list_trns_proc): Properly set retval when END
subcommand is in use.

* do-if.c: Fix ELSE and ELSE IF clauses.
(add_clause): Drop TARGET_INDEX argument and figure out the target
of the jump on our own.  The caller couldn't compensate for the
inserted BREAK transformation.  Updated all callers.