ggml : same IQ4_NL quantization for CPU/CUDA/Metal (#6196)
* Make quantize_row_iq4_nl do the same thing is quantization on CUDA
* Make quantize_row_iq4_nl do the same thing is quantization on CUDA
This time for real. backend-ops tests pass.
* Now fix test-quantize-fns
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Co-authored-by: Iwan Kawrakow <iwan.kawrakow@gmail.com>