go/runtime/host/multi: Propagate consensus sync requests to next version

[kostko]

Previously periodic consensus sync requests were not propagated to the next (e.g. upcoming) runtime version. This could result in the runtime's consensus view going stale which would make the attestations too old so they would be rejected during scheduling.

[codecov]

Codecov Report

Merging #5433 (7a9b9a6) into master (626172d) will decrease coverage by 0.60%.
Report is 1 commits behind head on master.
The diff coverage is 50.00%.

❗ Current head 7a9b9a6 differs from pull request most recent head 0ffa2f9. Consider uploading reports for the commit 0ffa2f9 to get more accurate results

@@            Coverage Diff             @@
##           master    #5433      +/-   ##
==========================================
- Coverage   66.96%   66.37%   -0.60%     
==========================================
  Files         533      533              
  Lines       56365    56375      +10     
==========================================
- Hits        37746    37419     -327     
- Misses      14236    14530     +294     
- Partials     4383     4426      +43     

Files	Coverage Δ
go/runtime/host/multi/multi.go	65.07% <50.00%> (-1.45%)	⬇️

... and 70 files with indirect coverage changes

[peternose]

Looks good, I would just reorder lines to keep host := agg.active.host together with if check, and host.Call together with its error handling.

We could also call the next host in a go routine, to speed things up. Not sure if needed, though.

Not part of this PR, but it looks like call could be removed from the retry. It would be more obvious that call to next rt will only be made once if retried multiple times.

	var (
		activeHost host.Runtime
		nextHost   host.Runtime
	)

	callFn := func() error {
		agg.l.RLock()
		defer agg.l.RUnlock()

		if agg.active == nil {
			return ErrNoActiveVersion
		}
		activeHost = agg.active.host

		if agg.next != nil {
			nextHost = agg.next.host
		}

		return nil
	}

[peternose]

In another PR we could also update the logger, e.g. logging.GetLogger("runtime/host/multi").With("id", id). I guess here the version is important, but it can also be read from the logs.