[mutter] tests/kvm: Don't run in parallel

[Marge Bot <marge-bot src gnome org>]

commit 43336251bdd804bb9d48a312c749ee5013b8e35b
Author: Jonas Ådahl <jadahl gmail com>
Date:   Fri Aug 5 12:15:58 2022 +0200

    tests/kvm: Don't run in parallel
    
    They can be quite heavy, as they load up one virtual machine each. If
    your system is already busy, this can easily cause them to time out
    instead of finish in time, as they all fight over the same limited
    amount of CPU and I/O time.
    
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2556>

 src/tests/kvm/meson.build | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/src/tests/kvm/meson.build b/src/tests/kvm/meson.build
index 17aaff1f5c..1d1b847f66 100644
--- a/src/tests/kvm/meson.build
+++ b/src/tests/kvm/meson.build
@@ -48,6 +48,7 @@ foreach test_case: privileged_tests
       test_case['executable'].full_path(),
       meson.current_build_dir(),
       vm_env,
-    ]
+    ],
+    is_parallel: false,
   )
 endforeach