We can't just run a single 'meson' command in the script as we need to
launch multiple long running processes inside the D-Bus session:
* The meson test invokation itself
* wireplumber
This was handled for the 'test' stages, but not for the 'dist' stage,
which as a result would fail due to wireplumber not being launched
causing any test using pipewire to timeout.
Address this by making run-tests.sh a more generic run-meson.sh that
launches wireplumber before running the actual meson command.
Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2204>
