Test that irksome and icepack are importable

Run on Jenkins to test --install XXX option.

Author: wence-

tests/regression/test_import_applications.py

@@ -4,7 +4,7 @@
 import sys
 
 
-@pytest.fixture(params=["gusto", "thetis"])
+@pytest.fixture(params=["gusto", "thetis", "irksome", "icepack"])
 def app(request):
     return request.param