tests: add test-fdmon-epoll

Test aio_disable_external(), which switches from fdmon-epoll back to
fdmon-poll. This resulted in an assertion failure that was fixed in the
previous patch.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200915120339.702938-3-stefanha@redhat.com>
3 files changed