Skip attach tests on FreeBSD due to bug in GDB.

Summary:
Despite successful attach GDB MI spits out a error message "Can't allocate registers". This gets caught by KDevMI layer and gets interpreted as error.
I've reported the problem to GDB upstream.

Reviewers: KDevelop

Subscribers: kdevelop-devel

Tags: KDevelop

Differential Revision: https://phabricator.kde.org/D14484