Robustify extract_leading_order tests.
Robustify extract_leading_order tests.

The order of the resulting tuple depends on hash, so we need to use set() to
get a platform independent test.

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