fix crash when looking up closure names in OptimizeBuiltinCalls transform (after running CreateClosureClasses transform)
fix crash when looking up closure names in OptimizeBuiltinCalls transform (after running CreateClosureClasses transform)

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