[WFLY-3477] Adding a new test to the existing test cases to cover the scenario where the context referrs to another server.
[WFLY-3477] Add support for specifying if the original connection is preferred or not for group to principal based searches.

Update the related test case to make use of this.
[WFLY-3477] Spelling correction identified during pull request review.
Merge pull request #6370 from darranl/WFLY-3477

[WFLY-3477] For group to principal LDAP searches we need the option to use the referral connection for the group search.