makefs: tests: Cleanup and remove default flags
Cleanup and remove default atf_check flags for clarity. The following
two lines are equivalent:
atf_check $cmd atf_check -s exit:0 -e empty -o empty $cmd
Update the links to the reference documents.
Remove the D_flag_cleanup function, as common_cleanup() for these
particular set of tests does two things:
- Unmount the md(4) device.
- Destroy the md(4) device.
Essentially, one should only call common_cleanup() if the test body
invokes mount_image(). This is not the case for D_flag_body().
No functional changes intended.
Reviewed by: ngie
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D54427