[Bug fortran/39772] add a correctness check for the size intrinsic to -fbounds-check

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=39772

--- Comment #12 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
Related to pr31243 for LEN.