ci/turnip: Use all 9 a618 runners at once for VK testing.

There are more boards in the collabora lab now, let's use them.  We were
spending just over 10 minutes inside of deqp-runner, so a bit more than
our target for the whole job.  Plus, we expect to be running more coverage
once VK_EXT_graphics_pipeline_library runs.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18620>

src/freedreno/ci/gitlab-ci.yml

@@ -128,7 +128,7 @@ a618_vk:
   extends:
     - .lava-test:arm64
     - .turnip-rules
-  parallel: 7
+  parallel: 9
   variables:
     VK_DRIVER: freedreno
     DEQP_SUITE: freedreno-a618-vk