test: even if a test fails, close the connection
test: even if a test fails, close the connection

Failure to close a connection causes all subsequent tests to fail
because "some grants are still mapped in".

Signed-off-by: David Scott <63c9eb0ea83039690fefa11afe17873ba8278a56@citrix.com>

samoht/ocaml-vchan,djs55/ocaml-vchan,samoht/ocaml-vchan,mirage/ocaml-vchan,djs55/ocaml-vchan,mirage/ocaml-vchan,mirage/ocaml-vchan,samoht/ocaml-vchan,djs55/ocaml-vchan