feat: add relaxed simd #445

Job	Run time
Build wasm	2m 50s
Run tests on Linux x86 (stable)	36s
Run tests on Linux arm64	2m 30s
Run tests on macOS arm64 (Apple M1)	55s
Run tests on Linux armv7	2m 45s
Run tests on Linux x86 (stable, no default features)	34s
Run tests on Linux x86 (nightly)	56s
Run tests on Linux x86 (nightly, no default features)	51s
	11m 57s

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