panfrost/ci: Smoke test spilling

Spilling is tricky and doesn't get much testing in CI. Run
a subset of dEQP-GLES2.functional.shaders.* with spilling forced to get spilling
tested in CI.

Signed-off-by: Alyssa Rosenzweig <alyssa@collabora.com>
Reviewed-by: Emma Anholt <emma@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/16314>

src/panfrost/ci/deqp-panfrost-g52.toml

@@ -41,3 +41,17 @@ deqp_args = [
     "--deqp-gl-config-name=rgba8888d24s8ms0",
 ]
 
+# Smoke test spilling
+[[deqp]]
+deqp = "/deqp/modules/gles2/deqp-gles2"
+caselists = ["/deqp/mustpass/gles2-master.txt"]
+include = ["functional.shaders"]
+deqp_args = [
+    "--deqp-surface-width=256", "--deqp-surface-height=256",
+    "--deqp-surface-type=pbuffer", "--deqp-visibility=hidden",
+    "--deqp-gl-config-name=rgba8888d24s8ms0",
+]
+prefix = "spill-"
+fraction = 2
+[deqp.env]
+BIFROST_MESA_DEBUG = "spill"