[Patch, Fortran] PR54687 - Fortran options cleanup (part 2)

[FX]

> Built and currently regtested on x86-64-gnu-linux.
> OK for the trunk?

OK.

I’m not sure exactly why we have a hardcoded minimal value of (2^16-1) for “max array constructor”, or a default max stack of 2^15. But that’s a separate issue.

Thanks,
FX