stream-clone: split the stream part out of test-persistent-nodemap.t
We want to test multiple variants, so let's make it an independent test.
Small adaptations and simplifications are needed in the test output as the
tested repository is now shorter.
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"phabricator.uri": "https://phab.mercurial-scm.org/",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}