* Implement `Swizzle` and `Splat` for interpreter
Implemented for the Cranelift interpreter:
- `Swizzle` to shuffle an `i8x16` SIMD vector based
on the indices specified in another vector of the same size.
- `Splat` to create a SIMD vector with all lanes having the same value.
Copyright (c) 2021, Arm Limited
* Fix old x86 backend failing test
Copyright (c) 2021, Arm Limited
* Represent i16x8 and above as hex
Copyright (c) 2021, Arm Limited