FiniteSet._complement: Don't use default_sort_key in sorting.
FiniteSet._complement: Don't use default_sort_key in sorting.

Some time ago I have made this method sort the elements by
default_sort_key.  This is redundant however, because _complement only
works for FiniteSet's containing numbers, which can be sorted directly,
without invoking default_sort_key.

bukzor/sympy,VaibhavAgarwalVA/sympy,srjoglekar246/sympy,sahmed95/sympy,dqnykamp/sympy,farhaanbukhsh/sympy,pbrady/sympy,kmacinnis/sympy,lidavidm/sympy,sunny94/temp,farhaanbukhsh/sympy,jerli/sympy,jerli/sympy,yukoba/sympy,drufat/sympy,chaffra/sympy,Vishluck/sympy,kaichogami/sympy,liangjiaxing/sympy,aktech/sympy,souravsingh/sympy,sahilshekhawat/sympy,souravsingh/sympy,Mitchkoens/sympy,dqnykamp/sympy,yashsharan/sympy,saurabhjn76/sympy,kmacinnis/sympy,Shaswat27/sympy,jaimahajan1997/sympy,liangjiaxing/sympy,lindsayad/sympy,AunShiLord/sympy,atsao72/sympy,ahhda/sympy,mafiya69/sympy,diofant/diofant,asm666/sympy,chaffra/sympy,sampadsaha5/sympy,mcdaniel67/sympy,Curious72/sympy,grevutiu-gabriel/sympy,Mitchkoens/sympy,hargup/sympy,Shaswat27/sympy,Mitchkoens/sympy,sahmed95/sympy,ChristinaZografou/sympy,emon10005/sympy,oliverlee/sympy,wyom/sympy,lindsayad/sympy,kevalds51/sympy,moble/sympy,jbbskinny/sympy,madan96/sympy,dqnykamp/sympy,pbrady/sympy,iamutkarshtiwari/sympy,debugger22/sympy,emon10005/sympy,moble/sympy,iamutkarshtiwari/sympy,rahuldan/sympy,vipulroxx/sympy,wanglongqi/sympy,mafiya69/sympy,abloomston/sympy,vipulroxx/sympy,Davidjohnwilson/sympy,skidzo/sympy,jamesblunt/sympy,cswiercz/sympy,jbbskinny/sympy,drufat/sympy,Designist/sympy,sampadsaha5/sympy,garvitr/sympy,hargup/sympy,skirpichev/omg,abloomston/sympy,yashsharan/sympy,mcdaniel67/sympy,jamesblunt/sympy,cccfran/sympy,kaichogami/sympy,shikil/sympy,hargup/sympy,ga7g08/sympy,wanglongqi/sympy,AkademieOlympia/sympy,bukzor/sympy,ga7g08/sympy,VaibhavAgarwalVA/sympy,meghana1995/sympy,jaimahajan1997/sympy,lindsayad/sympy,abhiii5459/sympy,abhiii5459/sympy,cccfran/sympy,atreyv/sympy,shipci/sympy,jbbskinny/sympy,Sumith1896/sympy,yashsharan/sympy,postvakje/sympy,VaibhavAgarwalVA/sympy,MridulS/sympy,oliverlee/sympy,yukoba/sympy,bukzor/sympy,Titan-C/sympy,MridulS/sympy,pandeyadarsh/sympy,atreyv/sympy,AkademieOlympia/sympy,meghana1995/sympy,Davidjohnwilson/sympy,pbrady/sympy,MechCoder/sympy,asm666/sympy,sahilshekhawat/sympy,kaushik94/sympy,MechCoder/sympy,postvakje/sympy,Gadal/sympy,AunShiLord/sympy,oliverlee/sympy,sahilshekhawat/sympy,mafiya69/sympy,sampadsaha5/sympy,saurabhjn76/sympy,drufat/sympy,Sumith1896/sympy,chaffra/sympy,amitjamadagni/sympy,kaushik94/sympy,pandeyadarsh/sympy,Curious72/sympy,ahhda/sympy,yukoba/sympy,sunny94/temp,kevalds51/sympy,madan96/sympy,jerli/sympy,Curious72/sympy,Gadal/sympy,flacjacket/sympy,shipci/sympy,ga7g08/sympy,Vishluck/sympy,shipci/sympy,Shaswat27/sympy,beni55/sympy,cccfran/sympy,garvitr/sympy,grevutiu-gabriel/sympy,Arafatk/sympy,Designist/sympy,Designist/sympy,Gadal/sympy,beni55/sympy,abloomston/sympy,maniteja123/sympy,rahuldan/sympy,kevalds51/sympy,debugger22/sympy,hrashk/sympy,ChristinaZografou/sympy,debugger22/sympy,atsao72/sympy,shikil/sympy,Titan-C/sympy,ahhda/sympy,vipulroxx/sympy,mcdaniel67/sympy,saurabhjn76/sympy,moble/sympy,madan96/sympy,Vishluck/sympy,lidavidm/sympy,kumarkrishna/sympy,sunny94/temp,jamesblunt/sympy,MridulS/sympy,aktech/sympy,kaichogami/sympy,kmacinnis/sympy,kaushik94/sympy,cswiercz/sympy,AkademieOlympia/sympy,pandeyadarsh/sympy,rahuldan/sympy,amitjamadagni/sympy,toolforger/sympy,aktech/sympy,postvakje/sympy,abhiii5459/sympy,atsao72/sympy,shikil/sympy,sahmed95/sympy,wyom/sympy,atreyv/sympy,asm666/sympy,MechCoder/sympy,Sumith1896/sympy,iamutkarshtiwari/sympy,Titan-C/sympy,souravsingh/sympy,skidzo/sympy,wanglongqi/sympy,skidzo/sympy,Arafatk/sympy,garvitr/sympy,hrashk/sympy,AunShiLord/sympy,lidavidm/sympy,kumarkrishna/sympy,Arafatk/sympy,cswiercz/sympy,emon10005/sympy,maniteja123/sympy,ChristinaZografou/sympy,grevutiu-gabriel/sympy,toolforger/sympy,kumarkrishna/sympy,toolforger/sympy,maniteja123/sympy,wyom/sympy,beni55/sympy,Davidjohnwilson/sympy,liangjiaxing/sympy,farhaanbukhsh/sympy,jaimahajan1997/sympy,meghana1995/sympy,hrashk/sympy