runtime: using wyrand for fastrand on linux/loong64

runtime: using wyrand for fastrand on linux/loong64

Benchmarks on linux/loong64:
name               old time/op    new time/op    delta
Fastrand           4.06ns ± 0%    3.60ns ± 0%    -11.29%  (p=0.000 n=32+27)
Fastrand64         7.20ns ± 0%    7.16ns ± 0%     -0.52%  (p=0.000 n=23+31)
FastrandHashiter   49.5ns ± 1%    48.9ns ± 2%     -1.24%  (p=0.000 n=32+32)
Fastrandn/2        4.45ns ± 0%    3.81ns ± 0%    -14.37%  (p=0.000 n=32+32)
Fastrandn/3        4.45ns ± 0%    3.81ns ± 0%    -14.32%  (p=0.000 n=32+32)
Fastrandn/4        4.45ns ± 0%    3.81ns ± 0%    -14.33%  (p=0.000 n=31+32)
Fastrandn/5        4.44ns ± 0%    3.81ns ± 0%    -14.26%  (p=0.000 n=31+30)

Change-Id: I0aba7d2331221426c44cc0d0dddecca3b585fda4
Reviewed-on: https://go-review.googlesource.com/c/go/+/446896
Reviewed-by: Keith Randall <khr@google.com>
Run-TryBot: Wayne Zuo <wdvxdr@golangcn.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Keith Randall <khr@golang.org>