top: exploit some of those new smaps_rollup provisions

top: exploit some of those new smaps_rollup provisions

My, how time flies. Here we are finally attending to a
2 year old issue at long last (well, at least top is).

In truth, this change was prompted by that more recent
issue #201 and simply represents my initial picks from
among those available with the new library provisions.

Note: we have to bump that rcfile version whenever new
fields are added. That will mean older top programs no
longer can read this top's rcfile. But that's Ok since
top offers a warning before replacing an older rcfile.

Doubtless, more smaps_rollup fields will be introduced
under top as we get more experience with this feature.
However, any such usage comes with tremendoud costs as
was reported for the previous patch and repeated here:

Here is a small preview of just what you will discover
when using this command line: time top/top -d0 -n1000.

------------------------------------ as a regular user
    with only PID + RES (statm)
real       0m2.605s
user       0m1.060s
sys        0m1.377s
    with only PID + RSS (smaps)
real      0m26.397s                    10x more costly
user       0m1.253s
sys       0m24.915s

----------------- as a root (thus smaps for all tasks)
    with only PID + RES (statm)
real       0m2.651s
user       0m1.177s
sys        0m1.286s
    with only PID + RSS (smaps)
real      0m33.040s                    12x more costly
user       0m1.256s
sys       0m31.533s

Reference(s):
. top/ps: add support for PSS reporting
https://gitlab.com/procps-ng/procps/-/issues/112
. ps: expose shared/private memory separately
https://gitlab.com/procps-ng/procps/-/issues/201

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