REGTESTS: cli: test the commands which change the run-time settings

REGTESTS: cli: test the commands which change the run-time settings

None of the CLI commands changing a run-time setting was covered: set
maxconn for the process, a frontend and a server, set rate-limit for
the connections and the sessions, set weight in absolute value and as a
percentage, get weight, set server state, disable/enable/shutdown
frontend, set profiling, set anon, set severity-output, set timeout,
set table, clear table and echo.

Each change is read back with the command which reports it, so that
both the setter and the reporter are exercised: "show info" for the
global limits, the "slim" and status columns of "show stat" for the
proxy and server limits and states, "get weight", "show profiling",
"show anon" and "show table".