top: add '4' toggle for 2 abreast cpu display, program

top: add '4' toggle for 2 abreast cpu display, program

In the back of my mind, I've always wanted to enable a
two abreast cpu display. Folks with massively parallel
machines must surely have been frustrated with the '1'
toggle when Off (individual cpus in the Summary Area).

So, I'll use that recently raised issue shown below as
a justification for finally implementing this feature.

Reference(s):
https://gitlab.com/procps-ng/procps/-/issues/172

Signed-off-by: Jim Warner <james.warner@comcast.net>