Stop using Mockito deprecated anyObject(), it's just an alias for any()

Change-Id: Ic6bfbb74f46086b88849b9d252d0c7eb6e81a2f9
Signed-off-by: Alexander Kurtakov <akurtako@redhat.com>
Reviewed-on: https://git.eclipse.org/r/c/platform/eclipse.platform.ui/+/188512
Tested-by: Platform Bot <platform-bot@eclipse.org>