erts: Rewrite hash_SUITE:4gb_bin tc to use less memory
erts: Rewrite hash_SUITE:4gb_bin tc to use less memory

The testcase has been rewritten to try its very best to
not keep the refc binaries used alive any longer than
strictly necessary.

Also, the GC calls now wait for the mseg cache to be flushed
before returning so that we know that the memory has been
returned to the OS.

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