pathDB test: add comparison of timestamps
pathDB test: add comparison of timestamps

The pathDB test previously did not compare the timestamps of segments.

GitOrigin-RevId: a4af2125c195e5f14ad7490fdc1ff0bd2eb840d2

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