s390x/intercept: Test invalid prefix argument to SET PREFIX

According to the architecture, SET PREFIX must try to access the new
prefix area and recognize an addressing exception if the area is not
accessible.
Test that the exception occurs when we try to set a prefix higher
than the available memory.

Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Message-Id: <20220627152412.2243255-1-scgl@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>