Revert "Drop test_series1_failing() introduced in PR #757, see test_simple1()"
Revert "Drop test_series1_failing() introduced in PR #757, see test_simple1()"

This reverts commit 754f3aa44b1e695e8195273232f2ad3e4cfae5da.

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