The Linux CI job names are too long and are not recognizable on the web
GUI unless you hover the widgets with the mouse to read tooltips. Remove
the "/testing" part (if people want to know exactly which Debian we use
for our builds, they can always look at the script) and move left the
differenciating parts (i.e. autotools/meson/clang/distcheck) so that
these are visible in a glance, even when ellipsing long job names.