Remove special cases in optimization of a simple let
Remove special cases in optimization of a simple let

Improve handling of #c_seq{}, making sure to simplify a #c_seq{}
as much as possible. With that improvement, we can remove some
special-case code from opt_simple_let_2/6.

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