t5516: remove ambiguity test (1)

t5516: remove ambiguity test (1)

This test tried to push into a remote with ambiguous refs in
remotes/$x/master and remotes/$y/master. However, the remote
never actually tells us about the refs/remotes hierarchy, so
we don't even see this ambiguity.

The test happened to pass because we were simply looking for
failure, and the test fails for another reason: the dst
refspec does not exist and does not begin with refs/, making
it invalid.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>