* fix _mm_castsi128_pd and _mm_castpd_si128 impls
The _mm_castX_Y SSE intrinsics are "reinterpreting" casts; LLVM's
simd_cast is a "converting" cast. Replace simd_cast with mem::transmute.
Fixes#55249
* Temporarily pin CI
* Fix i686 segfaults
* Fix wasm CI
Output of `wasm2wat` has changed!
* Fix AppVeyor with an older nightly