GitHub Actions: add genall tests

.github/workflows/ubuntu.yml

@@ -54,3 +54,11 @@ jobs:
         cd examples/kernel-exploit
         sudo ../../out-of-tree --log-level=debug kernel autogen --max=1
         sudo ../../out-of-tree --log-level=debug pew --threshold=0 --qemu-timeout=10m
+
+    - name: End-to-End Testing [Generate all Ubuntu 22.04 kernels]
+      run: |
+        sudo ../../out-of-tree kernel genall --distro=Ubuntu --ver=22.04
+
+    - name: End-to-End Testing [Generate all CentOS 7 kernels]
+      run: |
+        sudo ../../out-of-tree kernel genall --distro=CentOS --ver=7