kv: include conflicting request information in latch manager traces/logs

[nvanbenschoten]

The latch manager contains trace events and logs for conflicts in Manager.waitForSignal. This observability uses latch.String to present the span and the strength of the conflicting latch. However, it does not present information about the specific requests holding the latch or the requests acquiring the latch.

We should push down *BatchRequests into the spanlatch.Manager and include the output from BatchRequest.SafeFormat in latch.SafeFormat.

Jira issue: CRDB-33589

Epic CRDB-34227

[nvanbenschoten]

When doing this, we should store the *BatchRequest on the Guard and change latch from storing a *signals to a *Guard. This will avoid bloating the size of the latch struct.

[nvanbenschoten]

Will pair nicely with #114475.

[lyang24]

Hi Nathan, I thought about two ways of implementing the push down of *BatchRequest, which path do you recommend?

1. Make SequenceReq that take *BatchRequest as new parameter
2. Since majority of fields in Request struct at pkg/kv/kvserver/concurrency/concurrency_control.go are derived from batchRequest we can refactor Request struct to below this will require us changing how request is constructed in test.

type Request struct {
	BatchRequests *kvpb.BatchRequest
	MaxLockWaitQueueLength int
	PoisonPolicy poison.Policy
	LatchSpans *spanset.SpanSet
	LockSpans *lockspanset.LockSpanSet
}