[erts|net] Removed use of the 'HAVE_GETHOSTNAME' macro
[erts|net] Removed use of the 'HAVE_GETHOSTNAME' macro

Removed use of the 'HAVE_GETHOSTNAME' (config-) macro.
The gethostname function is assumed to be present!

OTP-16464

dumbbell/otp,potatosalad/otp,jj1bdx/otp,emacsmirror/erlang,rlipscombe/otp,dgud/otp,mikpe/otp,vinoski/otp,dgud/otp,isvilen/otp,erlang/otp,jj1bdx/otp,mikpe/otp,emacsmirror/erlang,potatosalad/otp,g-andrade/otp,mikpe/otp,erlang/otp,bjorng/otp,dgud/otp,erlang/otp,potatosalad/otp,bjorng/otp,isvilen/otp,bjorng/otp,erlang/otp,erlang/otp,erlang/otp,isvilen/otp,dgud/otp,rlipscombe/otp,dgud/otp,vinoski/otp,jj1bdx/otp,vinoski/otp,jj1bdx/otp,rlipscombe/otp,g-andrade/otp,erlang/otp,mikpe/otp,g-andrade/otp,rlipscombe/otp,jj1bdx/otp,bjorng/otp,vinoski/otp,mikpe/otp,vinoski/otp,dgud/otp,rlipscombe/otp,mikpe/otp,isvilen/otp,dumbbell/otp,isvilen/otp,rlipscombe/otp,dgud/otp,isvilen/otp,isvilen/otp,g-andrade/otp,g-andrade/otp,dumbbell/otp,erlang/otp,isvilen/otp,emacsmirror/erlang,rlipscombe/otp,mikpe/otp,g-andrade/otp,dumbbell/otp,g-andrade/otp,dumbbell/otp,potatosalad/otp,bjorng/otp,bjorng/otp,potatosalad/otp,vinoski/otp,erlang/otp,bjorng/otp,emacsmirror/erlang,emacsmirror/erlang,potatosalad/otp,bjorng/otp,emacsmirror/erlang,erlang/otp,emacsmirror/erlang,vinoski/otp,g-andrade/otp,potatosalad/otp,dumbbell/otp,potatosalad/otp,bjorng/otp,g-andrade/otp,emacsmirror/erlang,vinoski/otp,g-andrade/otp,jj1bdx/otp,jj1bdx/otp,rlipscombe/otp,potatosalad/otp,dgud/otp,dgud/otp,dumbbell/otp,bjorng/otp,isvilen/otp,emacsmirror/erlang,isvilen/otp,rlipscombe/otp,dumbbell/otp,mikpe/otp,emacsmirror/erlang,dumbbell/otp,vinoski/otp,vinoski/otp,dumbbell/otp,rlipscombe/otp,mikpe/otp,dgud/otp,jj1bdx/otp,mikpe/otp,jj1bdx/otp,jj1bdx/otp,potatosalad/otp