[2/2] Add, Mul, Pow: tests for is_comparable
[2/2] Add, Mul, Pow: tests for is_comparable

Unfortunately, previous patch (just new tests) somehow triggers caching bug, so
I'm XFAIL'ing what is affected.

I'm still investigating what the problem is, but let's merge this for now.

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