Fix EZP-20877: Improve unit test code coverage of eZ\Publish\Core\SignalSlot

Added unit tests for SignalSlot location service
Fix EZP-20877:  Improve unit test code coverage of eZ\Publish\Core\SignalSlot

Added unit tests for the SignalSlot URL wildcard service
Fix EZP-20877: Improve unit test code coverage of eZ\Publish\Core\SignalSlot

Added unit tests for the SignalSlot trash service