Revert "Rewrite heurisch() using Poly arithmetics"
Revert "Rewrite heurisch() using Poly arithmetics"

This reverts commit a701102e7554f62ef71729dc2c6df9ef96ec8bfa.

As noted in the commit message of that commit, this implementation is
much slower than the original Basic implementation, to the degree that
it is unusable for non-trivial integrals.  Therefore, we revert the
commit until Polys become faster.

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