gcc: modernize
gcc: modernize

- delete all options
- delete :recommended and :optional
- delete `arch` function (not present upstream)
- rearrange the code a bit to match upstream more
- delete Java block (not needed)
- bring the fortran test inline with upstream and enable it
- install gfortran symlink

Closes #17712.

Signed-off-by: Dawid Dziurla <c4a7db180859322ef5630a1dfc2805b5bc97fc25@gmail.com>

maxim-belkin/homebrew-core,Linuxbrew/homebrew-core,Linuxbrew/homebrew-core,rwhogg/homebrew-core,LinuxbrewTestBot/homebrew-core,rwhogg/homebrew-core,LinuxbrewTestBot/homebrew-core,maxim-belkin/homebrew-core