Add --enable-installed-tests=exclusive, fix installed case

The major reason to do this is that running tests *both* installed
and uninstalled in our CI is a mostly pointless waste of time.
Particularly given we have a few expensive tests.

We *do* have tests that only run uninstalled (since they require
the source code) like `test-symbols.sh`.

Hence, add `--enable-installed-tests=exclusive` to mean *only* do installed for
most tests.

We'll still have uninstalled coverage via the Travis/Debian configs, and we
could perhaps do another build with a subset of uninstalled tests, but I'm not
really concerned about it.

I'd like to do a renewed push for the InstalledTests model since
I feel it's just fundamentally better.  (`g-d-t-r` kind of sucks,
but then so does the automake runner).

Also while we're here - fix the CI to use the correct context,
which started this mess.

Closes: #837
Approved by: dbnicholson

tests/ci-build.sh

@@ -85,7 +85,6 @@ make="make -j${ci_parallel} V=1 VERBOSE=1"
 
 ../configure \
     --enable-always-build-tests \
-    --enable-installed-tests \
     ${ci_configopts}
     "$@"
 
@@ -106,12 +105,6 @@ if [ "$ci_sudo" = yes ] && [ "$ci_test" = yes ]; then
         ${make} installcheck || \
     maybe_fail_tests
     cat test/test-suite.log || :
-
-    env \
-        LD_LIBRARY_PATH=/usr/local/lib \
-        GI_TYPELIB_PATH=/usr/local/lib/girepository-1.0 \
-        gnome-desktop-testing-runner -d /usr/local/share ostree/ || \
-    maybe_fail_tests
 fi
 
 # vim:set sw=4 sts=4 et: