TOP-1078: Random bug fix of the day

This MR addresses the following:

• The manual configuration of SPEAD unicast routes in the P4 switch has been removed; this is done by CBF automatically and actually causes a race condition because we can't add the same routes twice.
• The manual configuration of SDP IP routes in the P4 switch has been replaced with basic routing; CBF tries to automatically create this route based on ARP-ing the IP address used in the scan configuration, and this causes a race condition where the CBF connector sometimes deletes our manually added route, causing the correlator output to go nowhere. There is no easy workaround for this issue right now, which is why we fall back to basic routing.
• The tests are now run in random order by default, to make it more likely that we spot dependencies between tests while developing.
• The processor admin modes are no longer being set to OFFLINE; if a processor is already ONLINE we keep it that way.