erts: Fix bug in stack walk on risc
erts: Fix bug in stack walk on risc

Symptom: Got ra==NULL at nsp==nsp_end
when running basic_SUITE:basic_arith on arm

why has this not been detected before?

ferd/otp,matwey/otp,uabboli/otp,vinoski/otp,bjorng/otp,falkevik/otp,dumbbell/otp,matwey/otp,fenollp/otp,bernardd/otp,tuncer/otp,tuncer/otp,isvilen/otp,uabboli/otp,dgud/otp,erlang/otp,fenollp/otp,lrascao/otp,RaimoNiskanen/otp,rlipscombe/otp,mikpe/otp,potatosalad/otp,rlipscombe/otp,rlipscombe/otp,lrascao/otp,dgud/otp,getong/otp,bernardd/otp,electricimp/otp,saleyn/otp,potatosalad/otp,RoadRunnr/otp,tuncer/otp,falkevik/otp,falkevik/otp,erlang/otp,isvilen/otp,kvakvs/otp,fenollp/otp,bjorng/otp,electricimp/otp,vinoski/otp,vladdu/otp,goertzenator/otp,getong/otp,saleyn/otp,bsmr-erlang/otp,RaimoNiskanen/otp,dgud/otp,emacsmirror/erlang,cobusc/otp,emacsmirror/erlang,lrascao/otp,RoadRunnr/otp,fenollp/otp,falkevik/otp,g-andrade/otp,cobusc/otp,RaimoNiskanen/otp,saleyn/otp,RaimoNiskanen/otp,bernardd/otp,getong/otp,dumbbell/otp,mikpe/otp,dgud/otp,legoscia/otp,goertzenator/otp,getong/otp,dumbbell/otp,g-andrade/otp,massemanet/otp,rlipscombe/otp,RoadRunnr/otp,tuncer/otp,bjorng/otp,RoadRunnr/otp,lrascao/otp,bernardd/otp,release-project/otp,massemanet/otp,bsmr-erlang/otp,emacsmirror/erlang,rlipscombe/otp,aboroska/otp,RaimoNiskanen/otp,saleyn/otp,fenollp/otp,rlipscombe/otp,aboroska/otp,isvilen/otp,RoadRunnr/otp,dgud/otp,dgud/otp,vladdu/otp,getong/otp,bernardd/otp,kvakvs/otp,jj1bdx/otp,release-project/otp,potatosalad/otp,uabboli/otp,ferd/otp,mikpe/otp,bernardd/otp,aboroska/otp,RaimoNiskanen/otp,mikpe/otp,rlipscombe/otp,RoadRunnr/otp,matwey/otp,release-project/otp,matwey/otp,mikpe/otp,uabboli/otp,dumbbell/otp,falkevik/otp,mikpe/otp,g-andrade/otp,saleyn/otp,getong/otp,cobusc/otp,cobusc/otp,isvilen/otp,saleyn/otp,bsmr-erlang/otp,bjorng/otp,kvakvs/otp,g-andrade/otp,vinoski/otp,dgud/otp,dumbbell/otp,lrascao/otp,falkevik/otp,legoscia/otp,jj1bdx/otp,matwey/otp,rlipscombe/otp,matwey/otp,aboroska/otp,emacsmirror/erlang,legoscia/otp,fenollp/otp,electricimp/otp,ferd/otp,goertzenator/otp,electricimp/otp,getong/otp,fenollp/otp,jj1bdx/otp,erlang/otp,saleyn/otp,bernardd/otp,bsmr-erlang/otp,goertzenator/otp,g-andrade/otp,kvakvs/otp,tuncer/otp,uabboli/otp,falkevik/otp,vladdu/otp,erlang/otp,potatosalad/otp,bernardd/otp,potatosalad/otp,potatosalad/otp,aboroska/otp,massemanet/otp,vladdu/otp,uabboli/otp,dumbbell/otp,massemanet/otp,bsmr-erlang/otp,vinoski/otp,vladdu/otp,vladdu/otp,vinoski/otp,emacsmirror/erlang,ferd/otp,electricimp/otp,kvakvs/otp,vinoski/otp,matwey/otp,isvilen/otp,dumbbell/otp,bjorng/otp,release-project/otp,massemanet/otp,electricimp/otp,goertzenator/otp,g-andrade/otp,massemanet/otp,release-project/otp,falkevik/otp,release-project/otp,potatosalad/otp,getong/otp,ferd/otp,electricimp/otp,erlang/otp,emacsmirror/erlang,jj1bdx/otp,legoscia/otp,erlang/otp,getong/otp,dgud/otp,vinoski/otp,mikpe/otp,tuncer/otp,bjorng/otp,ferd/otp,RoadRunnr/otp,emacsmirror/erlang,lrascao/otp,legoscia/otp,legoscia/otp,matwey/otp,bjorng/otp,fenollp/otp,rlipscombe/otp,saleyn/otp,massemanet/otp,jj1bdx/otp,bsmr-erlang/otp,getong/otp,cobusc/otp,release-project/otp,legoscia/otp,jj1bdx/otp,electricimp/otp,bernardd/otp,bsmr-erlang/otp,vinoski/otp,dumbbell/otp,goertzenator/otp,RoadRunnr/otp,lrascao/otp,cobusc/otp,erlang/otp,RaimoNiskanen/otp,jj1bdx/otp,aboroska/otp,kvakvs/otp,vinoski/otp,mikpe/otp,RoadRunnr/otp,ferd/otp,potatosalad/otp,vladdu/otp,ferd/otp,aboroska/otp,erlang/otp,tuncer/otp,rlipscombe/otp,RaimoNiskanen/otp,goertzenator/otp,erlang/otp,release-project/otp,release-project/otp,jj1bdx/otp,mikpe/otp,uabboli/otp,cobusc/otp,falkevik/otp,g-andrade/otp,kvakvs/otp,bjorng/otp,kvakvs/otp,massemanet/otp,vladdu/otp,g-andrade/otp,matwey/otp,erlang/otp,massemanet/otp,aboroska/otp,uabboli/otp,isvilen/otp,fenollp/otp,goertzenator/otp,tuncer/otp,dumbbell/otp,goertzenator/otp,ferd/otp,potatosalad/otp,kvakvs/otp,vinoski/otp,isvilen/otp,legoscia/otp,cobusc/otp,dgud/otp,aboroska/otp,jj1bdx/otp,vladdu/otp,mikpe/otp,potatosalad/otp,dumbbell/otp,legoscia/otp,bsmr-erlang/otp,uabboli/otp,saleyn/otp,bjorng/otp,emacsmirror/erlang,bjorng/otp,RaimoNiskanen/otp,isvilen/otp,dgud/otp,g-andrade/otp,isvilen/otp,tuncer/otp,isvilen/otp,jj1bdx/otp,emacsmirror/erlang,emacsmirror/erlang,bsmr-erlang/otp,g-andrade/otp,lrascao/otp,electricimp/otp,lrascao/otp