ci: consolidate aarch64 tests on GitHub runners

Currently we run aarch64 tests on both Cirrus CI and GitHub runners.
However, Cirrus CI fails with "Monthly compute limit exceeded!". This
change removes the redundant tests to streamline our CI process.

Signed-off-by: Radostin Stoyanov <rstoyanov@fedoraproject.org>

.github/workflows/aarch64-test.yaml

@@ -9,14 +9,16 @@ concurrency:
 
 jobs:
   build:
-    runs-on: ubuntu-24.04-arm
     strategy:
       matrix:
+        os: [ubuntu-24.04-arm, ubuntu-22.04-arm]
         target: [GCC=1, CLANG=1]
 
+    runs-on: ${{ matrix.os }}
+
     steps:
     - uses: actions/checkout@v4
-    - name: Run Tests ${{ matrix.target }}
+    - name: Run Tests ${{ matrix.target }} on ${{ matrix.os }}
       # Following tests are failing on the VMs:
       #  ./change_mnt_context --pidfile=change_mnt_context.pid --outfile=change_mnt_context.out
       #   45: ERR: change_mnt_context.c:23: mount (errno = 22 (Invalid argument))