patch 9.1.1491: missing out-of-memory checks in cmdexpand.c

patch 9.1.1491: missing out-of-memory checks in cmdexpand.c

Problem:  missing out-of-memory checks in cmdexpand.c
Solution: add out-of-memory checks for expand_files_and_dirs(),
          ExpandUserDefined() and ExpandUserList()
          (John Marriott)

closes: #17570

Signed-off-by: John Marriott <basilisk@internode.on.net>
Signed-off-by: Christian Brabandt <cb@256bit.org>