CA-90846: Consider adapter filter for multipath and control path tests

The XenCert utility accepts an adapter option but only uses it for
functional tests. Made changes to consider the filter for all other
applicable tests. Also, changed the argument from adapter name to
host number, eg host4

Signed-off-by: Chandrika Srinivasan <chandrika.srinivasan@citrix.com>
Can we still throw an obvious error in this case? Probably from outside the for-loop.