only run arm builds on kvm backendo

The qemu and uml backends are very slow doing arm build so just run it
on kvm builds; The testing on the other ones doesn't add so much value
especially now kvm capable runners are also available on github

.github/workflows/ci.yaml

@@ -125,17 +125,19 @@ jobs:
         test:
           - { name: "recipes", case: "recipes" }
           - { name: "templating", case: "templating", variables: " -t escaped:\\$ba\\'d\\$gers\\ snakes" }
-          - { name: "debian (amd64)", case: "debian", variables: "-t architecture:amd64" }
-          - { name: "debian (arm64)", case: "debian", variables: "-t architecture:arm64" }
-          - { name: "debian (armhf)", case: "debian", variables: "-t architecture:armhf" }
           - { name: "partitioning", case: "partitioning" }
           - { name: "msdos partitioning", case: "msdos" }
+          - { name: "debian (amd64)", case: "debian", variables: "-t architecture:amd64" }
         exclude:
           - backend: nofakemachine
             test: { name: "partitioning", case: "partitioning" }
           - backend: nofakemachine
             test: { name: "msdos partitioning", case: "msdos" }
         include:
+          - backend: kvm
+            test: { name: "debian (arm64)", case: "debian", variables: "-t architecture:arm64" }
+          - backend: kvm
+            test: { name: "debian (armhf)", case: "debian", variables: "-t architecture:armhf" }
           - backend: kvm
             test: { name: "arch", case: "arch" }
           - backend: kvm