Only one argument is accepted by the native host, which is an optional
path to a managed host assembly (aka the PowerShell console). If not
specified, lib/powershell/powershell.exe is used by default. All other
arguments are forwarded as-is to the managed host.
Rather than assuming that it's in the current directory. Later this will
be refactoring to choose the appropriate host assembly (for an
interactive shell, script, command list, or self-test) from the
`PWRSH_ROOT` path.