This change is motivated by the need to disable the default 30 seconds timeout
that Meson uses (see: https://gitlab.gnome.org/GNOME/glib/-/issues/2522), and
also by desire to specify extra options to run the check phase without having
to override it.
* guix/build-system/meson.scm (meson-build) <test-target>: Replace argument
with...
<test-options>: ... this one.
* guix/build/meson-build-system.scm (check): Invoke 'meson test' instead of
'ninja test-target', as the former is configurable via options.
* doc/guix.texi (Build Systems) <meson-build-system>: Update doc.
dfcc96d8f4