Touch o.e.pde.ui.tests for the signature change in assertj.

Change-Id: Ia9cec9f5f3459d16d1765a6a4674ba2433e5d341
Reviewed-on: https://git.eclipse.org/r/c/pde/eclipse.pde.ui/+/188528
Tested-by: PDE Bot <pde-bot@eclipse.org>
Reviewed-by: Alexander Kurtakov <akurtako@redhat.com>