sbws measures some relays 100x lower than Torflow

Hi,

I've received multiple reports from relay operators who are concerned their relays are being measured too low.

At the moment, we only have 2 Torflow instances in the network, and 3 sbws instances. So bad sbws measurements can lower any relay's bandwidth, regardless of the Torflow measurement.

Here is one report: https://lists.torproject.org/pipermail/tor-relays/2020-March/018321.html

At the moment, the bandwidths are:

moria1 494 maatuska 4 longclaw 5

https://consensus-health.torproject.org/consensus-health-2020-03-31-21-00.html#6E1DA4C0B0C05FB721B42329C47A20DA22908AEB

I have also received a similar report privately from a large relay operator.

This bug could be related to #33009 (moved) or #30733 (moved).