unsupported x86 sse2 intrinsic `llvm.x86.sse2.psll.q`

Thanks for cranelift, it's a great project!

I have a project where I'm hitting the following message when building with `rustc_codegen_cranelift`
```
warning: unsupported x86 llvm intrinsic llvm.x86.sse2.psll.q; replacing with trap
```