The source project of this merge request has been removed.
flatpak: Update tests
Add -Dinstall_tests_true option and change retro-reftest path.
Reflects the changes in retro-gtk commits 4e98fc85fd5c5b158b2e623e6fe5b461a00e0f73 and 6a63d3ce781c4143b955879985851a2fdf6e5554.