Add in extra connections tests

Test reporting back to gerrit as a different user.
Test multiple gerrit instances.

Squashed with: Assign fake connections to test class dynamically

As multiple connections can be configured for testing purposes, it makes
more sense to be able to access them all comfortably.

Drawback of this change is, that the dynamicism makes the code less
readable and less obvious.
Previously: If50567dd5a087e9fe46cd4e30f9e0562cda794d7

Co-Authored-By: Jan Hruban <jan.hruban@gooddata.com>

Change-Id: I4652799c8b9a626bd2f7f6996d09c95da2953936
6 files changed