[polys] Improve sdm_groebner further.
[polys] Improve sdm_groebner further.

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