WIP ARM Neon/AVX2 SIMD implementation. #764

Job	Run time
Ruby memcheck	52s
ruby-versions / Generate Ruby versions	2s
ubuntu-22.04 2.7	1m 17s
ubuntu-22.04 3.0	49s
ubuntu-22.04 3.1	36s
ubuntu-22.04 3.2	28s
ubuntu-22.04 3.3	49s
ubuntu-22.04 3.4	32s
ubuntu-22.04 head	1m 20s
ubuntu-22.04 jruby	1m 6s
ubuntu-22.04 jruby-head	1m 2s
macos-13 2.7	1m 37s
macos-13 3.0	34s
macos-13 3.1	38s
macos-13 3.2	31s
macos-13 3.3	36s
macos-13 3.4	36s
macos-13 head	38s
macos-13 jruby	1m 9s
macos-13 jruby-head	1m 5s
macos-14 2.7	59s
macos-14 3.0	21s
macos-14 3.1	32s
macos-14 3.2	18s
macos-14 3.3	21s
macos-14 3.4	19s
macos-14 head	18s
macos-14 jruby	46s
macos-14 jruby-head	36s
windows-latest 2.7	4m 58s
windows-latest 3.0	2m 10s
windows-latest 3.1	2m 18s
windows-latest 3.2	2m 31s
windows-latest 3.3	2m 32s
windows-latest 3.4	3m 58s
windows-latest head	2m 18s
windows-latest mswin	1m 33s
ubuntu-latest jruby-9.4	1m 7s
macos-latest truffleruby-head	58s
ubuntu-latest truffleruby-head	2m 6s
	47m 16s

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