Fix compiler crash in isinstance optimization.
Fix compiler crash in isinstance optimization.

c-blake/cython,ABcDexter/cython,dahebolangkuan/cython,dahebolangkuan/cython,cython/cython,hhsprings/cython,JelleZijlstra/cython,encukou/cython,roxyboy/cython,mrGeen/cython,andreasvc/cython,ABcDexter/cython,hhsprings/cython,mcanthony/cython,c-blake/cython,hhsprings/cython,dahebolangkuan/cython,fabianrost84/cython,encukou/cython,marscher/cython,mcanthony/cython,fabianrost84/cython,andreasvc/cython,roxyboy/cython,madjar/cython,ChristopherHogan/cython,marscher/cython,JelleZijlstra/cython,ABcDexter/cython,dahebolangkuan/cython,andreasvc/cython,madjar/cython,da-woods/cython,scoder/cython,marscher/cython,ABcDexter/cython,dahebolangkuan/cython,JelleZijlstra/cython,acrispin/cython,achernet/cython,roxyboy/cython,encukou/cython,madjar/cython,encukou/cython,roxyboy/cython,mrGeen/cython,marscher/cython,ABcDexter/cython,andreasvc/cython,hhsprings/cython,madjar/cython,cython/cython,c-blake/cython,hickford/cython,JelleZijlstra/cython,mcanthony/cython,mcanthony/cython,encukou/cython,hhsprings/cython,scoder/cython,ChristopherHogan/cython,c-blake/cython,andreasvc/cython,acrispin/cython,acrispin/cython,hickford/cython,fperez/cython,mrGeen/cython,fperez/cython,scoder/cython,mrGeen/cython,roxyboy/cython,achernet/cython,achernet/cython,fabianrost84/cython,slonik-az/cython,JelleZijlstra/cython,acrispin/cython,ChristopherHogan/cython,c-blake/cython,hickford/cython,da-woods/cython,cython/cython,hickford/cython,achernet/cython,mrGeen/cython,acrispin/cython,slonik-az/cython,slonik-az/cython,marscher/cython,scoder/cython,fabianrost84/cython,cython/cython,fperez/cython,madjar/cython,fabianrost84/cython,fperez/cython,da-woods/cython,slonik-az/cython,da-woods/cython,hickford/cython,achernet/cython,slonik-az/cython,fperez/cython,mcanthony/cython