nvk+zink/ci: add rusticl testing

Adds almost 2 minutes of runtime but we don't care anyway because this
is a nightly job :)

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30073>

src/gallium/drivers/zink/ci/deqp-zink-nvk.toml

@@ -60,3 +60,10 @@ timeout = 180.0
   PIGLIT_NO_WINDOW = "1"
   PIGLIT_PLATFORM = "gbm"
   WAFFLE_PLATFORM = "gbm"
+
+[[piglit]]
+piglit_folder = "/piglit"
+profile = "cl"
+process_isolation = true
+  [piglit.env]
+  RUSTICL_ENABLE = "zink"

src/gallium/drivers/zink/ci/gitlab-ci-inc.yml

@@ -78,6 +78,7 @@
     - !reference [.test, rules]
     - !reference [.nvk-valve-rules, rules]
     - !reference [.zink-common-rules, rules]
+    - !reference [.rusticl-rules, rules]
 
 .zink-nvk-manual-rules:
   stage: layered-backends-nightly
@@ -86,6 +87,7 @@
     - !reference [.test, rules]
     - !reference [.nvk-valve-manual-rules, rules]
     - !reference [.zink-common-manual-rules, rules]
+    - !reference [.rusticl-manual-rules, rules]
 
 .zink-turnip-collabora-rules:
   stage: layered-backends