games/dMagnetic: Update to 0.22

• Update to 0.22
• Improve tests

Changelog:

• http://freshcode.club/projects/dmagnetic
• http://www.dettus.net/dMagnetic/old_releases.html

PR: 244101
Reported by: Thomas Dettbarn (maintainer)
Approved by: tcberner (mentor)
Differential Revision: https://reviews.freebsd.org/D23762