In case 'test_wcfs_pintimeout_kill' is successful, WCFS kills the
client process. In order to prevent WCFS from killing the full
testing process, we therefore need to encapsulate the test code into
a subprocess, so that only this subprocess is killed if the test is
successful. Because of moving our test to a subprocess, we also need
to explicitly catch exceptions to mark the test as failed in case of
any error.