replaced a bunch of vpermpd instructions with vpermilpd and vperm2f128

power9 cgemm/ctrmm. new sgemm 8x16

Signed-off-by: Piotr Kubaj <pkubaj@anongoth.pl>

improved power9 zgemm,sgemm

As noted in #1912 and comment on #1942, the combined implementation happens to "do the right thing" on hardfp, but cannot return both value and index on softfp where they would have to share the return register

* Mark iamax_sse.S as unsuitable for MIN due to issue #2116
* Use iamax.S rather than iamax_sse.S for ISMIN/ISAMIN on all x86_64 as workaround for #2116

Disable the SkyLakeX DGEMMIxCOPY kernels as well

#1955

as a stopgap measure for https://github.com/numpy/numpy/issues/13401 as mentioned in #1955

sgemm/strmm kernel for power9

Add (C)BLAS extension ?sum

as trivial copies of the respective ?asum kernels with the ABS and vflpsb calls removed

as trivial copy of ?asum with the fabs calls removed

as trivial copy of ?asum with the fabs calls removed

as trivial copy of ?asum with the fabs replaced by fmov to preserve code structure

as trivial copy of ?asum with the fabs replaced by fmr to preserve code structure

as trivial copy of ?asum with the fabs replaced by mov to preserve code structure

as trivial copy of ?asum with the fabs calls removed

as trivial copy of asum with the fabs calls removed

as trivial copies of the respective ?asum kernels with the fabs calls removed

(trivial copies of the respective ?asum with the fabs calls removed)