Merge topic 'file-archive-args'

7c83265e59 file(ARCHIVE*): Simplify acceptance of empty list arguments
dfff470d15 file(ARCHIVE*): Add test for keyword arguments with missing values

Acked-by: Kitware Robot <kwrobot@kitware.com>
Acked-by: buildbot <buildbot@kitware.com>
Merge-request: !7427