DROP BEFORE MERGE Verify offload test uses GPU

Author: dsroberts

.github/workflows/core.yml

@@ -597,6 +597,11 @@ jobs:
           firedrake-check
         timeout-minutes: 10
 
+      - name: Verify GPU usage
+        run: |
+          export PETSC_OPTIONS="${PETSC_OPTIONS} -log_view_gpu_time -log_view"
+           python3 ./firedrake/tests/firedrake/offload/test_poisson_offloading_pc.py
+
       - name: Post-run cleanup
         if: always()
         run: |