pathmgr: fix flaky unit test (#2159)
pathmgr: fix flaky unit test (#2159)

Also make test run faster by deleting deprecated sleeps.

netsec-ethz/scion,netsec-ethz/scion,Oncilla/scion,Oncilla/scion,netsec-ethz/scion,Oncilla/scion,Oncilla/scion,netsec-ethz/scion