drop benchmarks/ubench

I genuinely don't think there is any loss in ditching this.
The source hasn't been touched in 25 years, the homepage doesn't exist,
and it is not a benchmark of anything.

CPU performance is measured by timing this:

unsigned cpucalc(pmin) /* performs rather senseless calcs */
unsigned pmin;
{
double x,y;
unsigned i,j,k=0;
i=pmin;
for (j=0;j<i;j++)
if ( j%67 )
k+=j%(i-j+1);
else
{
x=i-j;
y=log(1.0+x);
x=abs(sqrt(y/(2.0+x))*(x*cos(atan(y/(3.0+x)))+y*sin(atan(y/(4.0+x)))));
if ( x > 10.0 )
y=pow(1.0+j/(5.0+x),y/(6.0+x));
else
y=pow(1.0+y/(1+j),x);
x=x*exp(1.0/(1.0+y));
k+=x;
}
i=k%99;
if ( i==0 ) i++;
return i;
}

It "will spawn about 2 concurrent processes for each CPU available
on the system. This ensures all available raw CPU horsepower is used."
This is my PC during that CPU benchmark:

CPU0: 100% user, 0.0% nice, 0.0% sys, 0.0% spin, 0.0% intr, 0.0% idle
CPU1: 0.0% user, 0.0% nice, 0.0% sys, 0.0% spin, 0.0% intr, 100% idle
CPU2: 0.0% user, 0.0% nice, 0.0% sys, 0.0% spin, 0.0% intr, 100% idle
CPU3: 0.0% user, 0.0% nice, 0.0% sys, 0.0% spin, 0.0% intr, 100% idle
CPU4: 100% user, 0.0% nice, 0.0% sys, 0.0% spin, 0.0% intr, 0.0% idle
CPU5: 0.0% user, 0.0% nice, 0.0% sys, 0.0% spin, 0.0% intr, 100% idle
CPU6: 0.0% user, 0.0% nice, 0.0% sys, 0.0% spin, 0.0% intr, 100% idle
CPU7: 0.0% user, 0.0% nice, 0.0% sys, 0.0% spin, 0.0% intr, 100% idle

Similar lolz for mem performance; the average of the two is
"the Ubench AVG benchmark which is supposed to represent the true
computing power of the system."

Jan