sys_pre_expand: Remove vestiges of variable usage tracking
sys_pre_expand: Remove vestiges of variable usage tracking

Before the Core Erlang passes were introduced a long time ago,
sys_pre_expand used to track used and new variables in order to
do lambda lifting (i.e. transform funs into ordinary Erlang
functions). Lambda lifting is now done in v3_kernel.

Remove the few remaining vestiges of variable tracking in the
comments and the code.

neeraj9/otp,aboroska/otp,ferd/otp,potatosalad/otp,kvakvs/otp,massemanet/otp,electricimp/otp,isvilen/otp,rlipscombe/otp,saleyn/otp,electricimp/otp,vladdu/otp,RaimoNiskanen/otp,saleyn/otp,kvakvs/otp,basho/otp,RaimoNiskanen/otp,electricimp/otp,RoadRunnr/otp,lightcyphers/otp,goertzenator/otp,dgud/otp,mikpe/otp,release-project/otp,electricimp/otp,basho/otp,neeraj9/otp,isvilen/otp,tuncer/otp,falkevik/otp,tuncer/otp,lightcyphers/otp,potatosalad/otp,getong/otp,basho/otp,neeraj9/otp,falkevik/otp,release-project/otp,getong/otp,psyeugenic/otp,bsmr-erlang/otp,uabboli/otp,g-andrade/otp,bsmr-erlang/otp,potatosalad/otp,getong/otp,vinoski/otp,bernardd/otp,dgud/otp,lemenkov/otp,goertzenator/otp,getong/otp,legoscia/otp,lemenkov/otp,vladdu/otp,ferd/otp,aboroska/otp,uabboli/otp,g-andrade/otp,lemenkov/otp,tuncer/otp,dgud/otp,RaimoNiskanen/otp,erlang/otp,lightcyphers/otp,rlipscombe/otp,emacsmirror/erlang,cobusc/otp,legoscia/otp,neeraj9/otp,rlipscombe/otp,bsmr-erlang/otp,lrascao/otp,aboroska/otp,saleyn/otp,RoadRunnr/otp,jj1bdx/otp,isvilen/otp,RaimoNiskanen/otp,emacsmirror/erlang,basho/otp,tuncer/otp,dumbbell/otp,falkevik/otp,weisslj/otp,goertzenator/otp,weisslj/otp,emacsmirror/erlang,erlang/otp,jj1bdx/otp,electricimp/otp,release-project/otp,massemanet/otp,weisslj/otp,jj1bdx/otp,matwey/otp,g-andrade/otp,g-andrade/otp,electricimp/otp,g-andrade/otp,aboroska/otp,bsmr-erlang/otp,mikpe/otp,goertzenator/otp,emile/otp,matwey/otp,rlipscombe/otp,basho/otp,dgud/otp,kvakvs/otp,basho/otp,getong/otp,legoscia/otp,matwey/otp,dgud/otp,fenollp/otp,dumbbell/otp,vladdu/otp,aboroska/otp,lrascao/otp,ferd/otp,lightcyphers/otp,mikpe/otp,RaimoNiskanen/otp,cobusc/otp,kvakvs/otp,RaimoNiskanen/otp,falkevik/otp,erlang/otp,lrascao/otp,vinoski/otp,falkevik/otp,RoadRunnr/otp,saleyn/otp,saleyn/otp,potatosalad/otp,lemenkov/otp,fenollp/otp,ahmedshafeeq/otp,ahmedshafeeq/otp,bjorng/otp,bjorng/otp,uabboli/otp,lrascao/otp,massemanet/otp,bugs-erlang-org/otp,ferd/otp,bugs-erlang-org/otp,emile/otp,potatosalad/otp,cobusc/otp,g-andrade/otp,bugs-erlang-org/otp,vladdu/otp,kvakvs/otp,massemanet/otp,bugs-erlang-org/otp,rlipscombe/otp,lrascao/otp,vinoski/otp,kvakvs/otp,dgud/otp,legoscia/otp,RaimoNiskanen/otp,bsmr-erlang/otp,release-project/otp,ahmedshafeeq/otp,mikpe/otp,massemanet/otp,release-project/otp,weisslj/otp,aboroska/otp,bjorng/otp,jj1bdx/otp,bsmr-erlang/otp,bjorng/otp,g-andrade/otp,psyeugenic/otp,mikpe/otp,vinoski/otp,lemenkov/otp,lightcyphers/otp,massemanet/otp,massemanet/otp,ahmedshafeeq/otp,dgud/otp,bjorng/otp,jj1bdx/otp,mikpe/otp,weisslj/otp,vinoski/otp,vladdu/otp,matwey/otp,lrascao/otp,basho/otp,mikpe/otp,falkevik/otp,tuncer/otp,lrascao/otp,jj1bdx/otp,ferd/otp,rlipscombe/otp,rlipscombe/otp,dgud/otp,basho/otp,dumbbell/otp,matwey/otp,lemenkov/otp,erlang/otp,cobusc/otp,dumbbell/otp,cobusc/otp,electricimp/otp,mikpe/otp,basho/otp,RoadRunnr/otp,emile/otp,RoadRunnr/otp,emile/otp,release-project/otp,lrascao/otp,tuncer/otp,RaimoNiskanen/otp,emile/otp,legoscia/otp,dumbbell/otp,psyeugenic/otp,aboroska/otp,saleyn/otp,kvakvs/otp,kvakvs/otp,bsmr-erlang/otp,goertzenator/otp,psyeugenic/otp,getong/otp,neeraj9/otp,bjorng/otp,emacsmirror/erlang,saleyn/otp,dumbbell/otp,fenollp/otp,isvilen/otp,falkevik/otp,emile/otp,lightcyphers/otp,bernardd/otp,fenollp/otp,cobusc/otp,RaimoNiskanen/otp,getong/otp,tuncer/otp,vinoski/otp,emile/otp,electricimp/otp,matwey/otp,bernardd/otp,jj1bdx/otp,getong/otp,g-andrade/otp,goertzenator/otp,jj1bdx/otp,ferd/otp,emacsmirror/erlang,ahmedshafeeq/otp,rlipscombe/otp,rlipscombe/otp,lrascao/otp,ahmedshafeeq/otp,aboroska/otp,ahmedshafeeq/otp,isvilen/otp,fenollp/otp,dumbbell/otp,g-andrade/otp,legoscia/otp,emacsmirror/erlang,RoadRunnr/otp,lightcyphers/otp,matwey/otp,bugs-erlang-org/otp,dgud/otp,isvilen/otp,RoadRunnr/otp,bernardd/otp,vinoski/otp,emacsmirror/erlang,isvilen/otp,vinoski/otp,uabboli/otp,bernardd/otp,bsmr-erlang/otp,uabboli/otp,emacsmirror/erlang,potatosalad/otp,erlang/otp,jj1bdx/otp,tuncer/otp,isvilen/otp,weisslj/otp,vinoski/otp,dumbbell/otp,ahmedshafeeq/otp,fenollp/otp,bjorng/otp,erlang/otp,emacsmirror/erlang,mikpe/otp,massemanet/otp,matwey/otp,mikpe/otp,lemenkov/otp,bugs-erlang-org/otp,psyeugenic/otp,goertzenator/otp,kvakvs/otp,uabboli/otp,neeraj9/otp,bjorng/otp,weisslj/otp,psyeugenic/otp,bsmr-erlang/otp,getong/otp,vladdu/otp,neeraj9/otp,release-project/otp,goertzenator/otp,rlipscombe/otp,erlang/otp,dumbbell/otp,potatosalad/otp,vinoski/otp,fenollp/otp,getong/otp,legoscia/otp,matwey/otp,cobusc/otp,psyeugenic/otp,potatosalad/otp,electricimp/otp,massemanet/otp,cobusc/otp,saleyn/otp,legoscia/otp,fenollp/otp,falkevik/otp,ferd/otp,weisslj/otp,ferd/otp,bernardd/otp,dgud/otp,bjorng/otp,bugs-erlang-org/otp,uabboli/otp,uabboli/otp,emacsmirror/erlang,ferd/otp,lemenkov/otp,erlang/otp,tuncer/otp,potatosalad/otp,isvilen/otp,vladdu/otp,legoscia/otp,fenollp/otp,bernardd/otp,emile/otp,bjorng/otp,emile/otp,erlang/otp,bernardd/otp,lightcyphers/otp,aboroska/otp,isvilen/otp,uabboli/otp,RoadRunnr/otp,bugs-erlang-org/otp,weisslj/otp,jj1bdx/otp,neeraj9/otp,release-project/otp,psyeugenic/otp,vladdu/otp,falkevik/otp,erlang/otp,dumbbell/otp,saleyn/otp,bernardd/otp,ahmedshafeeq/otp,g-andrade/otp,goertzenator/otp,RoadRunnr/otp,vladdu/otp,release-project/otp,potatosalad/otp