The default assert.soon() timeout was raised to 5 minutes from 30 seconds as of commit:
https://github.com/mongodb/mongo/commit/64f3646bc8f09d275ed38e3fe05274a254c57daf

Replica set monitor refresh is 30 seconds as of 3.3.12.
https://github.com/mongodb/mongo/blob/3.3.12/src/mongo/client/replica_set_monitor.cpp#L165

Prior to raising the timeout, mongos_no_replica_set_refresh.js was sometimes failing if the mongos refreshed its replica set monitor just before a replica set node was removed, so we should send a higher timeout in the assert.soon() calls in mongos_no_replica_set_refresh.js in case the default assert.soon() timeout is lowered again.