io.c: Make io_list_vec_len() less general
io.c: Make io_list_vec_len() less general

io_list_vec_len() is slightly more general than it needs to be.
Specifically:

* The only caller always passes ERL_SMALL_IO_BIN_LIMIT as the
  value for the bin_limit parameter, so the bin_limit parameter
  can be eliminated.

* The only caller never passes any NULL pointers, so there is
  no need test the pointers before writing through them.

bugs-erlang-org/otp,jj1bdx/otp,ferd/otp,ahmedshafeeq/otp,uabboli/otp,vic/otp,goertzenator/otp,electricimp/otp,sitexa/otp,vladdu/otp,matwey/otp,matwey/otp,basho/otp,rlipscombe/otp,haguenau/otp,derek121/otp,massemanet/otp,massemanet/otp,falkevik/otp,bugs-erlang-org/otp,sitexa/otp,yangchengjian/otp,rlipscombe/otp,jj1bdx/otp,bsmr-erlang/otp,jamesruan/otp,bjorng/otp,haguenau/otp,c-rack/otp,release-project/otp,matwey/otp,RJ/otp,paladim/otp,fenollp/otp,emacsmirror/erlang,schlagert/otp,neeraj9/otp,vinoski/otp,Teino1978-Corp/erlang-otp,dumbbell/otp,emile/otp,c-rack/otp,RaimoNiskanen/otp,vic/otp,schlagert/otp,johanclaesson/otp,lucafavatella/otp,RGafiyatullin/otp,jamesruan/otp,getong/otp,getong/otp,benoitc/otp-1,vladdu/otp,ahmedshafeeq/otp,dgud/otp,RoadRunnr/otp,jj1bdx/otp,basho/otp,legoscia/otp,derek121/otp,isvilen/otp,gjaldon/otp,mikpe/otp,haguenau/otp,isvilen/otp,saleyn/otp,entropiae/otp,vic/otp,legoscia/otp,haguenau/otp,rlipscombe/otp,ferd/otp,basho/otp,klarna/otp,enikki/otp,msantos/otp,cobusc/otp,platinumthinker/otp,release-project/otp,lantti/otp,bugs-erlang-org/otp,erlang/otp,mikpe/otp,bjorng/otp,riverrun/otp,falkevik/otp,uabboli/otp,haguenau/otp,Teino1978-Corp/otp,vinoski/otp,dgud/otp,beni55/otp,lrascao/otp,lianghaivv/otp,RichMorin/otp,bjorng/otp,ahmedshafeeq/otp,vinoski/otp,emacsmirror/erlang,jamesruan/otp,potatosalad/otp,isvilen/otp,emile/otp,RichMorin/otp,sitexa/otp,fenollp/otp,cobusc/otp,vinoski/otp,sammoth-wazoku/otp,goertzenator/otp,dgud/otp,potatosalad/otp,mikpe/otp,matwey/otp,uabboli/otp,sammoth-wazoku/otp,johanclaesson/otp,marquisthunder/otp,weisslj/otp,erlang/otp,cnbin/otp,legoscia/otp,lightcyphers/otp,platinumthinker/otp,g-andrade/otp,bsmr-erlang/otp,mikpe/otp,lhslll/otp,hairyhum/otp,erlang/otp,NOMORECOFFEE/otp,lucafavatella/otp,jj1bdx/otp,vinoski/otp,ader1990/otp,paladim/otp,gjaldon/otp,aboroska/otp,cobusc/otp,uabboli/otp,getong/otp,sitexa/otp,electricimp/otp,kvakvs/otp,bernardd/otp,jj1bdx/otp,goertzenator/otp,jemsbhai/otp,mujiatong/otp,entropiae/otp,RaimoNiskanen/otp,saleyn/otp,isvilen/otp,uabboli/otp,lemenkov/otp,bsmr-erlang/otp,mikpe/otp,RJ/otp,derek121/otp,cnbin/otp,tuncer/otp,g-andrade/otp,vinoski/otp,ahmedshafeeq/otp,lrascao/otp,ahmedshafeeq/otp,yangchengjian/otp,derek121/otp,sdebnath/otp,kvakvs/otp,getong/otp,bernardd/otp,emacsmirror/erlang,Teino1978-Corp/otp,krishnakumar4a4/otp,ader1990/otp,Teino1978-Corp/erlang-otp,krishnakumar4a4/otp,neeraj9/otp,lianghaivv/otp,electricimp/otp,jemsbhai/otp,dumbbell/otp,lantti/otp,vic/otp,massemanet/otp,erlang/otp,bjorng/otp,enikki/otp,palas/otp,legoscia/otp,release-project/otp,jinshana/otp,getong/otp,RaimoNiskanen/otp,schlagert/otp,msantos/otp,jemsbhai/otp,psyeugenic/otp,RaimoNiskanen/otp,saleyn/otp,RJ/otp,riverrun/otp,RoadRunnr/otp,ader1990/otp,VincentHHL/otp,theom/otp,johanclaesson/otp,lantti/otp,jamesruan/otp,entropiae/otp,vinoski/otp,fenollp/otp,haguenau/otp,basho/otp,isvilen/otp,jamesruan/otp,lrascao/otp,marquisthunder/otp,VincentHHL/otp,palas/otp,ader1990/otp,ahmedshafeeq/otp,getong/otp,lianghaivv/otp,goertzenator/otp,bjorng/otp,ferd/otp,marquisthunder/otp,falkevik/otp,emacsmirror/erlang,basho/otp,GinjaNinja32/otp,saleyn/otp,falkevik/otp,theom/otp,yangchengjian/otp,Teino1978-Corp/erlang-otp,RoadRunnr/otp,hairyhum/otp,weisslj/otp,bjorng/otp,lhslll/otp,ahmedshafeeq/otp,lianghaivv/otp,vladdu/otp,lemenkov/otp,riverrun/otp,fenollp/otp,stolen/otp,ferd/otp,c-rack/otp,lianghaivv/otp,kvakvs/otp,lightcyphers/otp,jinshana/otp,weisslj/otp,weisslj/otp,jj1bdx/otp,paladim/otp,fenollp/otp,vic/otp,msantos/otp,derek121/otp,lhslll/otp,legoscia/otp,dgud/otp,platinumthinker/otp,lhslll/otp,VincentHHL/otp,RGafiyatullin/otp,vladdu/otp,kvakvs/otp,weisslj/otp,getong/otp,massemanet/otp,aboroska/otp,NOMORECOFFEE/otp,vladdu/otp,lemenkov/otp,riverrun/otp,bsmr-erlang/otp,GinjaNinja32/otp,GinjaNinja32/otp,aboroska/otp,matwey/otp,psyeugenic/otp,massemanet/otp,bjorng/otp,haguenau/otp,marquisthunder/otp,jemsbhai/otp,cobusc/otp,legoscia/otp,johanclaesson/otp,RoadRunnr/otp,mujiatong/otp,rlipscombe/otp,RJ/otp,dgud/otp,mikpe/otp,fenollp/otp,release-project/otp,vic/otp,RaimoNiskanen/otp,lianghaivv/otp,beni55/otp,palas/otp,release-project/otp,dumbbell/otp,hairyhum/otp,jinshana/otp,mikpe/otp,g-andrade/otp,fenollp/otp,gjaldon/otp,sammoth-wazoku/otp,falkevik/otp,rlipscombe/otp,basho/otp,benoitc/otp-1,cnbin/otp,msantos/otp,NOMORECOFFEE/otp,dumbbell/otp,vladdu/otp,beni55/otp,electricimp/otp,schlagert/otp,psyeugenic/otp,mujiatong/otp,ferd/otp,aboroska/otp,basho/otp,emacsmirror/erlang,yangchengjian/otp,neeraj9/otp,stolen/otp,GinjaNinja32/otp,palas/otp,release-project/otp,RichMorin/otp,lianghaivv/otp,uabboli/otp,RaimoNiskanen/otp,krishnakumar4a4/otp,erlang/otp,matwey/otp,sammoth-wazoku/otp,psyeugenic/otp,lucafavatella/otp,bernardd/otp,uabboli/otp,theom/otp,mujiatong/otp,kvakvs/otp,marquisthunder/otp,Teino1978-Corp/otp,awetzel/otp,yangchengjian/otp,benoitc/otp-1,entropiae/otp,ferd/otp,RichMorin/otp,dumbbell/otp,kvakvs/otp,schlagert/otp,klarna/otp,g-andrade/otp,sdebnath/otp,g-andrade/otp,theom/otp,paladim/otp,emile/otp,vic/otp,emile/otp,ader1990/otp,entropiae/otp,psyeugenic/otp,jamesruan/otp,saleyn/otp,mikpe/otp,cobusc/otp,basho/otp,GinjaNinja32/otp,palas/otp,stolen/otp,dgud/otp,sdebnath/otp,aboroska/otp,neeraj9/otp,hairyhum/otp,enikki/otp,weisslj/otp,awetzel/otp,g-andrade/otp,mikpe/otp,sammoth-wazoku/otp,bernardd/otp,uabboli/otp,lrascao/otp,potatosalad/otp,yangchengjian/otp,jj1bdx/otp,awetzel/otp,cnbin/otp,cnbin/otp,lightcyphers/otp,goertzenator/otp,yangchengjian/otp,tuncer/otp,potatosalad/otp,paladim/otp,bsmr-erlang/otp,vinoski/otp,bugs-erlang-org/otp,bjorng/otp,jinshana/otp,potatosalad/otp,riverrun/otp,gjaldon/otp,saleyn/otp,sammoth-wazoku/otp,massemanet/otp,bugs-erlang-org/otp,vic/otp,beni55/otp,release-project/otp,dgud/otp,msantos/otp,lantti/otp,goertzenator/otp,lrascao/otp,emile/otp,psyeugenic/otp,kvakvs/otp,RoadRunnr/otp,platinumthinker/otp,paulcager/otp,cnbin/otp,lucafavatella/otp,emacsmirror/erlang,cobusc/otp,g-andrade/otp,erlang/otp,stolen/otp,emacsmirror/erlang,mujiatong/otp,Teino1978-Corp/otp,sdebnath/otp,gjaldon/otp,goertzenator/otp,paulcager/otp,sdebnath/otp,getong/otp,RaimoNiskanen/otp,Teino1978-Corp/erlang-otp,klarna/otp,isvilen/otp,jamesruan/otp,marquisthunder/otp,kvakvs/otp,platinumthinker/otp,jj1bdx/otp,tuncer/otp,klarna/otp,potatosalad/otp,hairyhum/otp,falkevik/otp,isvilen/otp,msantos/otp,ahmedshafeeq/otp,cnbin/otp,ferd/otp,saleyn/otp,derek121/otp,paulcager/otp,vladdu/otp,getong/otp,johanclaesson/otp,Teino1978-Corp/otp,krishnakumar4a4/otp,sdebnath/otp,rlipscombe/otp,aboroska/otp,jamesruan/otp,tuncer/otp,sitexa/otp,lhslll/otp,psyeugenic/otp,release-project/otp,jj1bdx/otp,benoitc/otp-1,hairyhum/otp,tuncer/otp,lantti/otp,vinoski/otp,dumbbell/otp,ader1990/otp,tuncer/otp,lrascao/otp,legoscia/otp,sitexa/otp,emacsmirror/erlang,erlang/otp,sitexa/otp,neeraj9/otp,beni55/otp,mikpe/otp,dumbbell/otp,legoscia/otp,gjaldon/otp,schlagert/otp,lhslll/otp,gjaldon/otp,neeraj9/otp,goertzenator/otp,NOMORECOFFEE/otp,VincentHHL/otp,theom/otp,legoscia/otp,RGafiyatullin/otp,g-andrade/otp,RoadRunnr/otp,RGafiyatullin/otp,c-rack/otp,lantti/otp,saleyn/otp,erlang/otp,sdebnath/otp,jemsbhai/otp,jinshana/otp,jemsbhai/otp,bjorng/otp,awetzel/otp,lianghaivv/otp,bsmr-erlang/otp,uabboli/otp,aboroska/otp,palas/otp,beni55/otp,tuncer/otp,derek121/otp,derek121/otp,bernardd/otp,Teino1978-Corp/otp,stolen/otp,dumbbell/otp,benoitc/otp-1,schlagert/otp,jj1bdx/otp,beni55/otp,krishnakumar4a4/otp,matwey/otp,potatosalad/otp,erlang/otp,hairyhum/otp,lantti/otp,klarna/otp,lightcyphers/otp,GinjaNinja32/otp,benoitc/otp-1,lucafavatella/otp,bsmr-erlang/otp,bugs-erlang-org/otp,falkevik/otp,weisslj/otp,weisslj/otp,lightcyphers/otp,marquisthunder/otp,goertzenator/otp,stolen/otp,jinshana/otp,fenollp/otp,lrascao/otp,emile/otp,sammoth-wazoku/otp,bernardd/otp,aboroska/otp,yangchengjian/otp,krishnakumar4a4/otp,RichMorin/otp,msantos/otp,platinumthinker/otp,klarna/otp,electricimp/otp,potatosalad/otp,cobusc/otp,RGafiyatullin/otp,emacsmirror/erlang,jinshana/otp,lrascao/otp,electricimp/otp,lemenkov/otp,massemanet/otp,massemanet/otp,isvilen/otp,c-rack/otp,johanclaesson/otp,isvilen/otp,awetzel/otp,potatosalad/otp,dgud/otp,marquisthunder/otp,rlipscombe/otp,lantti/otp,bernardd/otp,theom/otp,c-rack/otp,lightcyphers/otp,dumbbell/otp,awetzel/otp,NOMORECOFFEE/otp,rlipscombe/otp,riverrun/otp,bugs-erlang-org/otp,RGafiyatullin/otp,neeraj9/otp,platinumthinker/otp,palas/otp,entropiae/otp,ahmedshafeeq/otp,VincentHHL/otp,enikki/otp,ferd/otp,haguenau/otp,awetzel/otp,stolen/otp,RJ/otp,schlagert/otp,jinshana/otp,krishnakumar4a4/otp,sammoth-wazoku/otp,electricimp/otp,weisslj/otp,theom/otp,RGafiyatullin/otp,lucafavatella/otp,matwey/otp,VincentHHL/otp,mujiatong/otp,c-rack/otp,RichMorin/otp,vladdu/otp,awetzel/otp,bjorng/otp,mujiatong/otp,paulcager/otp,RaimoNiskanen/otp,msantos/otp,Teino1978-Corp/otp,bernardd/otp,dgud/otp,palas/otp,enikki/otp,NOMORECOFFEE/otp,cobusc/otp,paladim/otp,aboroska/otp,paulcager/otp,cnbin/otp,paulcager/otp,electricimp/otp,ader1990/otp,Teino1978-Corp/erlang-otp,Teino1978-Corp/otp,stolen/otp,entropiae/otp,fenollp/otp,basho/otp,bernardd/otp,lemenkov/otp,paladim/otp,falkevik/otp,GinjaNinja32/otp,klarna/otp,kvakvs/otp,riverrun/otp,g-andrade/otp,emile/otp,jemsbhai/otp,mujiatong/otp,dgud/otp,sdebnath/otp,lemenkov/otp,johanclaesson/otp,bsmr-erlang/otp,RGafiyatullin/otp,emile/otp,gjaldon/otp,RichMorin/otp,RoadRunnr/otp,tuncer/otp,riverrun/otp,tuncer/otp,saleyn/otp,g-andrade/otp,getong/otp,release-project/otp,lrascao/otp,lhslll/otp,massemanet/otp,Teino1978-Corp/erlang-otp,Teino1978-Corp/erlang-otp,platinumthinker/otp,RJ/otp,Teino1978-Corp/erlang-otp,matwey/otp,benoitc/otp-1,lemenkov/otp,theom/otp,lightcyphers/otp,enikki/otp,jemsbhai/otp,sitexa/otp,bugs-erlang-org/otp,VincentHHL/otp,beni55/otp,emile/otp,RJ/otp,RichMorin/otp,rlipscombe/otp,enikki/otp,electricimp/otp,ferd/otp,krishnakumar4a4/otp,lucafavatella/otp,vinoski/otp,benoitc/otp-1,erlang/otp,NOMORECOFFEE/otp,VincentHHL/otp,bsmr-erlang/otp,paladim/otp,enikki/otp,c-rack/otp,potatosalad/otp,lightcyphers/otp,RJ/otp,vladdu/otp,rlipscombe/otp,RaimoNiskanen/otp,lhslll/otp,falkevik/otp,RoadRunnr/otp,dumbbell/otp,isvilen/otp,hairyhum/otp,klarna/otp,neeraj9/otp,psyeugenic/otp,GinjaNinja32/otp,paulcager/otp,RoadRunnr/otp,johanclaesson/otp,lemenkov/otp,lucafavatella/otp,entropiae/otp,NOMORECOFFEE/otp,paulcager/otp,ader1990/otp,emacsmirror/erlang