Cirrus: Add Debian functional tests

.cirrus.yml

@@ -168,13 +168,25 @@ task:
     GOX_TAGS: ""
 
 task:
-  name: "Functional Tests Ubuntu Go $GO_VERSION$MODULES_NAME"
+  name: "Functional Tests $CI_DISTRO Go $GO_VERSION$MODULES_NAME"
-  compute_engine_instance:
+  alias: "Functional Tests"
-    image_project: cirrus-images
+  matrix:
-    image: family/docker-builder
+    - compute_engine_instance:
-    platform: linux
+        image_project: debian-cloud
-    cpu: 1
+        image: family/debian-11
-    memory: 1G
+        platform: linux
+        cpu: 1
+        memory: 1G
+      env:
+        CI_DISTRO: debian
+    - compute_engine_instance:
+        image_project: cirrus-images
+        image: family/docker-builder
+        platform: linux
+        cpu: 1
+        memory: 1G
+      env:
+        CI_DISTRO: ubuntu
   bitcoind_cache:
     folder: /tmp/bitcoind
     populate_script: mkdir -p /tmp/bitcoind
@@ -300,7 +312,7 @@ task:
     - ShellCheck
     - Unit Tests
     - Cross-Compile
-    - Functional Tests Ubuntu Go latest
+    - Functional Tests
   bin_cache:
     folder: "idist"
     fingerprint_script: