* sverker/remove-nif-reload:
  erts: Cuddle nif_SUITE:consume_timeslice
  erts: Remove old doc note for erlang:load_nif
  erts: Remove deprecated nif 'reload' feature
  erts: Fix trace_nif_SUITE to load nif lib only once

Anywhere but the beam sources we shouldn't #include "erl_nif.h", because
what "erl_nif.h" does is: (1) fail to find it outside of -I dirs, (2)
then treat it as if it was written like <erl_nif.h>. Using <erl_nif.h>
skips (1).

More information can be found in 6.10.2 of the C standard.

Because the examples use "erl_nif.h", NIF projects in the Erlang
ecosystem copy this verbatim and make the same mistake.

and instead let erlang:load_nif/2 return {error, {reload, _}}
before even trying to load the library
if a NIF library has already been successfully loaded
for the calling module instance.