* iq3_xxs_r4: 1st shot on Zen4
PP-512: 107 t/s -> 137 t/s
TG-128(1 thread): 2.64 t/s -> 3.44 t/s
* iq4_xxs_r4: WIP
* iq4_xxs_r4: 1st shot at AVX2
Note: there is a bug in the AVX2 implementation for nrc_y = 1
for IQ quants with blocks of 32. I have fixed it for now by
using the nrc_y > 1 implementation (which works) also for nrc_y = 1.
* iq3_xxs_r4: NEON
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Co-authored-by: Iwan Kawrakow <iwan.kawrakow@gmail.com>