Add x86_vcvtudq2ps instruction

This instruction converts i32x4 to f32x4 in several AVX512 feature sets.

cranelift/codegen/src/isa/aarch64/lower_inst.rs

@@ -2066,6 +2066,7 @@ pub(crate) fn lower_insn_to_regs<C: LowerCtx<I = Inst>>(
         | Opcode::X86Packss
         | Opcode::X86Punpckh
         | Opcode::X86Punpckl
+        | Opcode::X86Vcvtudq2ps
         | Opcode::X86ElfTlsGetAddr
         | Opcode::X86MachoTlsGetAddr => {
             panic!("x86-specific opcode in supposedly arch-neutral IR!");