GHSA-XM67-587Q-R2VW wasmtime vulnerable to miscompilation of `i8x16.select` with the same inputs on x86_64

Impact Wasmtime's code generation backend, Cranelift, has a bug on x8664 platforms for the WebAssembly i8x16.select instruction which will produce the wrong results when the same operand is provided to the instruction and some of the selected indices are greater than 16. There is an off-by-one...