by making p_estcpu fixpt_t. PR/31542.
1. schedcpu() decreases p_estcpu of all processes
every seconds, by at least 1 regardless of load average.
2. schedclock() increases p_estcpu of curproc by 1,
at about 16 hz.
in the consequence, if a system has >16 processes
with runnable lwps, their p_estcpu are not likely increased.
by making p_estcpu fixpt_t, we can decay it more slowly
when loadavg is high. (ie. solve #1.)
i left kinfo_proc2::p_estcpu (ie. ps -O cpu) scaled because i have
no idea about its absolute value's usage other than debugging,
for which raw values are more valuable.
8ab7495c2d