This VM integration test spawns Gnome, monado-service,
stardust-xr-server, flatland and weston-cliptest and tests that the
functionality works correctly. The result is a screenshot. If any
program in the test produces an exit code above 0 it will fail the test,
graphical rendering bugs should be visible in the resulting screenshot
* flake: use allowBuiltInFetchGit to prevent narHash reproducibility issues
using the builtin fetcher allows fetching git dependencies with only the ref and without storing the narHash for the fixed-output-derivation
* gitignore: add nix result symlinks
