(*) if we are already throwing a Wrapped*Exception, get the
exception using cppu::getCaughtexception.

(*) when catching and then immediately throwing UNO exceptions,
use cppu::getCaughtException to prevent exception slicing

(*) if we are going to catch an exception and then
immediately throw a RuntimeException, rather throw a
WrappedTargetRuntimeException and preserve the original exception information.

Change-Id: Ia7a501a50ae0e6f4d05186333c8517fdcb17d558
Reviewed-on: https://gerrit.libreoffice.org/54692Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>