Various Fixes and enhancements in x86 intrinsics

Updated the x86-intel.xml to be a more recent update of Intel Intrinsics Guide (v3.6.8)
Added functionality to auto-generate a missing-x86.md for ease of implementation
Updated disassembly to allow windows-gnu targets (they have the same implementation as linux targets, as that uses objdump from binutils, and binutils is a dependency of GCC). Add the x86_64-pc-windows-gnu target in CI
Fixed some of the stream intrinsics.
modified floating-point reduce-add and reduce-mul intrinsics to NOT use simd_reduce_add_unordered and simd_reduce_mul_unordered as Intel specifies a strict associativity. Follow GCC and hand-implement the associativity ourselves (#1533)
Fixed _load_mask32 etc in AVX512BW (they should have taken a __mmask32/__mmask64 pointer, but took u32/u64 pointer)
As moves never modify any flags, add preserves_flags to the asm! blocks for moves
Fix _mm_loadu_si64 (it had target-feature sse, but needs sse2), _mm256_extract_epi64, _mm256_extract_epi32, _mm256_cvtsi256_si32 (these had target-feature avx2, but need avx).
Fixed _mm_cvtt intrinsics (they were actually calling vcvtss2si, when they should call vcvttss2si)
Removed all MMX support from stdarch-verify, and made the target-feature verification stricter
Implemented the missing intrinsics mentioned in #1178 with feature-gate simd-x86-updates (rust-lang/rust#126936)
Fixed _mm512_kunpackb
Modified the reduce-max and reduce-min intrinsics to preserve associativity specified by Intel and to use the comparison function they described (which is NOT maxnum from LLVM)
Bumped the OS in CI Docker containers to Ubunto 24.04 (except for in armv7-unknown-linux-gnueabihf and x86_64-unknown-linux-gnu-emulated)

Modifying fma has been moved to #1597 Masked load/stores are on standby due to rust-lang/rust#126919

rust-lang / stdarch

Various Fixes and enhancements in x86 intrinsics #1594