ci: Do an explicit NIR validation-enabled pass on freedreno a630.

We disable it for most of the CTS because it's slow, but let's do a
fractional run to make sure that we don't hit any obvious failures.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5089>
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 981d306..c1b0fb6 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -827,6 +827,8 @@
     # Do a little testing with gmem and bypass forced.
     - DEQP_RUN_SUFFIX=-bypass FD_MESA_DEBUG=nogmem DEQP_EXPECTED_FAILS=deqp-freedreno-a630-bypass-fails.txt ./install/deqp-runner.sh
     - DEQP_RUN_SUFFIX=-gmem FD_MESA_DEBUG=nobypass ./install/deqp-runner.sh
+    # Check that we don't get obvious nir validation failures (though it's too expensive to run for the full CTS)
+    - DEQP_RUN_SUFFIX=-validate NIR_VALIDATE=1 ./install/deqp-runner.sh
 
 .baremetal-test:
   extends: