Modify PMT tests for directory environments

The beaker host['distmoduledir'] variable is meaningful if the
host is using directory environments (e.g 'production').

This commit updates the helper methods for validating that a module
is (or not) installed on the host by iterating over the modulepath
if a specific modulepath is not provided.

The calls to these helper methods have been updated for the change
in parameter ordering in the helper methods.