erts: Fix verify_nc in distribution suite
erts: Fix verify_nc in distribution suite

When the calling process is trapping exits a stray message
will end up in the mailbox which is problematic. This change
uses a monitor instead.

bsmr-erlang/otp,isvilen/otp,jj1bdx/otp,emacsmirror/erlang,dumbbell/otp,bjorng/otp,aboroska/otp,erlang/otp,kvakvs/otp,dgud/otp,dgud/otp,RoadRunnr/otp,getong/otp,rlipscombe/otp,potatosalad/otp,dgud/otp,getong/otp,lrascao/otp,rlipscombe/otp,lrascao/otp,aboroska/otp,bjorng/otp,bjorng/otp,getong/otp,emacsmirror/erlang,vladdu/otp,kvakvs/otp,aboroska/otp,getong/otp,vinoski/otp,uabboli/otp,bjorng/otp,bjorng/otp,vladdu/otp,dumbbell/otp,dumbbell/otp,isvilen/otp,dgud/otp,isvilen/otp,potatosalad/otp,kvakvs/otp,g-andrade/otp,dgud/otp,legoscia/otp,dgud/otp,g-andrade/otp,bsmr-erlang/otp,jj1bdx/otp,isvilen/otp,legoscia/otp,ferd/otp,potatosalad/otp,lrascao/otp,erlang/otp,getong/otp,ferd/otp,isvilen/otp,emacsmirror/erlang,bsmr-erlang/otp,potatosalad/otp,rlipscombe/otp,lrascao/otp,ferd/otp,vladdu/otp,dumbbell/otp,vinoski/otp,ferd/otp,emacsmirror/erlang,jj1bdx/otp,isvilen/otp,jj1bdx/otp,getong/otp,vinoski/otp,RoadRunnr/otp,electricimp/otp,dumbbell/otp,mikpe/otp,mikpe/otp,legoscia/otp,g-andrade/otp,dgud/otp,electricimp/otp,uabboli/otp,RoadRunnr/otp,emacsmirror/erlang,uabboli/otp,uabboli/otp,g-andrade/otp,bjorng/otp,potatosalad/otp,uabboli/otp,jj1bdx/otp,electricimp/otp,erlang/otp,potatosalad/otp,electricimp/otp,ferd/otp,kvakvs/otp,g-andrade/otp,legoscia/otp,bjorng/otp,lrascao/otp,jj1bdx/otp,electricimp/otp,potatosalad/otp,dumbbell/otp,legoscia/otp,kvakvs/otp,jj1bdx/otp,bsmr-erlang/otp,g-andrade/otp,bsmr-erlang/otp,isvilen/otp,dgud/otp,bsmr-erlang/otp,legoscia/otp,erlang/otp,emacsmirror/erlang,legoscia/otp,uabboli/otp,RoadRunnr/otp,potatosalad/otp,mikpe/otp,emacsmirror/erlang,jj1bdx/otp,aboroska/otp,erlang/otp,erlang/otp,vinoski/otp,potatosalad/otp,vinoski/otp,vladdu/otp,erlang/otp,g-andrade/otp,mikpe/otp,erlang/otp,bjorng/otp,ferd/otp,lrascao/otp,dumbbell/otp,ferd/otp,RoadRunnr/otp,RoadRunnr/otp,aboroska/otp,potatosalad/otp,legoscia/otp,mikpe/otp,rlipscombe/otp,mikpe/otp,rlipscombe/otp,dumbbell/otp,dumbbell/otp,vinoski/otp,erlang/otp,emacsmirror/erlang,g-andrade/otp,RoadRunnr/otp,vladdu/otp,getong/otp,lrascao/otp,kvakvs/otp,kvakvs/otp,isvilen/otp,bsmr-erlang/otp,vladdu/otp,emacsmirror/erlang,uabboli/otp,uabboli/otp,aboroska/otp,electricimp/otp,uabboli/otp,bsmr-erlang/otp,mikpe/otp,lrascao/otp,aboroska/otp,rlipscombe/otp,dumbbell/otp,getong/otp,dgud/otp,erlang/otp,rlipscombe/otp,getong/otp,legoscia/otp,electricimp/otp,g-andrade/otp,RoadRunnr/otp,electricimp/otp,vinoski/otp,isvilen/otp,electricimp/otp,emacsmirror/erlang,vinoski/otp,kvakvs/otp,mikpe/otp,lrascao/otp,bsmr-erlang/otp,bjorng/otp,getong/otp,isvilen/otp,dgud/otp,mikpe/otp,kvakvs/otp,RoadRunnr/otp,jj1bdx/otp,bjorng/otp,mikpe/otp,vladdu/otp,g-andrade/otp,jj1bdx/otp,rlipscombe/otp,vladdu/otp,rlipscombe/otp,rlipscombe/otp,aboroska/otp,ferd/otp,vinoski/otp,ferd/otp,vinoski/otp,vladdu/otp,aboroska/otp