cli: client commands using the RPC client code report undesirable warnings about latency jumps

[knz]

Describe the problem

When a CLI command is invoked that also performs RPC calls (e.g. cockroach debug zip), it currently activates the RPC latency monitor code which produces warnings when the latency is irregular. For example:

$ cockroach debug zip  f.zip
...
W220706 22:23:32.399339 16 2@rpc/pkg/rpc/clock_offset.go:216 [rnode=63,raddr=dataservices-cockroach-426e6718c609f177.elb.us-east-1.amazonaws.com:26257,class=system,heartbeat] 1 latency jump (prev avg 5.05ms, current 301.29ms)
...

And then the command still terminates.

This is a problem because it causes the user to be alarmed whereas there is absolutely no consequence in the CLI command to an irregular latency.

Expected behavior

CLI commands should run the RPC client code with latency warnings disabled.

Jira issue: CRDB-17410