Performance regression between 1.74.1 and 1.75.0

https://github.com/Nugine/simd-benches/actions/runs/8495251262

LLVM failed to emit vpavgb for _mm256_avg_epu8.
Blaming https://github.com/rust-lang/stdarch/pull/1477

https://github.com/rust-lang/rust/issues/124216