[fortran,patch] Fix PR 36186, wrong handling of BOZ in CMPLX

[Tobias Burnus]

FX wrote:
> Attached patch fixes handling of BOZ in CMPLX, DCMPLX and COMPLEX: 
> when they're not simplified (for example because only *one* arg is a 
> constant or BOZ), the one argument that's a BOZ is then never 
> converted. This now takes place in the simplification routine, before 
> bailing out, because it's the simplest place to do so. Due to that, we 
> also accepted invalid too-large BOZ.
>
> Bootstrapped and regtested on x86_64-linux, coming with two testcases. 
> OK to commit?
OK.

Tobias