(fix) Have REPORTTIME_LENGTHY cover zsh REPORTTIME

In the command running-time reporting system, have the
`REPORTTIME_LENGTHY` and `REPORTTIME_LENGTHY_COMMANDS` shell parameters
affect the standard zsh `REPORTTIME` behavior as well as the
`cmd-running-time-reporting-*` behavior, as the documentation
(`cmd-running-time-reporting help`) implies.
Add `set-REPORTTIME` zsh function

Add a `set-REPORTTIME` zsh function, which enables one to set
`REPORTTIME` after shell initialization, despite the command
running-time reporting system being overly complicated.
Add `test-busyloop` zsh function

Add a `test-busyloop` zsh function, which, for testing purposes, spins
in a loop for the specified number of seconds.