`create-exe`: Triage errors

[xdoardo]

This ticket unites the existing issues on create-exe:

`wasmer create-exe` generates broken executable. · Issue #5450 · wasmerio/wasmer

Executable produced by `create-exe` with `--llvm` switch is malformed · Issue #5287 · wasmerio/wasmer

Windows create-exe fail even for GNU target · Issue #5301 · wasmerio/wasmer

We should triage the errors and make sure that create-exe works as expected.

[xdoardo]

Fixed with #5512 and #5506.