py: Make mp_obj_print() handle null object w/o segfault if debug build.
py: Make mp_obj_print() handle null object w/o segfault if debug build.

Happens regularly when used for debugging.

pozetroninc/micropython,cwyark/micropython,ernesto-g/micropython,xhat/micropython,pozetroninc/micropython,slzatz/micropython,adafruit/circuitpython,mpalomer/micropython,warner83/micropython,ryannathans/micropython,cnoviello/micropython,mhoffma/micropython,feilongfl/micropython,AriZuu/micropython,adafruit/micropython,micropython/micropython-esp32,EcmaXp/micropython,henriknelson/micropython,alex-robbins/micropython,ChuckM/micropython,slzatz/micropython,puuu/micropython,stonegithubs/micropython,tuc-osg/micropython,mgyenik/micropython,micropython/micropython-esp32,jlillest/micropython,martinribelotta/micropython,deshipu/micropython,toolmacher/micropython,MrSurly/micropython-esp32,drrk/micropython,supergis/micropython,dxxb/micropython,micropython/micropython-esp32,KISSMonX/micropython,henriknelson/micropython,cnoviello/micropython,kostyll/micropython,turbinenreiter/micropython,swegener/micropython,tuc-osg/micropython,jlillest/micropython,tuc-osg/micropython,xuxiaoxin/micropython,alex-robbins/micropython,Timmenem/micropython,drrk/micropython,galenhz/micropython,ChuckM/micropython,noahchense/micropython,tobbad/micropython,adafruit/micropython,dmazzella/micropython,ganshun666/micropython,matthewelse/micropython,dinau/micropython,oopy/micropython,blmorris/micropython,tdautc19841202/micropython,lbattraw/micropython,suda/micropython,infinnovation/micropython,firstval/micropython,lbattraw/micropython,suda/micropython,ryannathans/micropython,TDAbboud/micropython,deshipu/micropython,adafruit/micropython,adafruit/circuitpython,SungEun-Steve-Kim/test-mp,puuu/micropython,tdautc19841202/micropython,matthewelse/micropython,kostyll/micropython,dmazzella/micropython,kostyll/micropython,bvernoux/micropython,rubencabrera/micropython,ernesto-g/micropython,stonegithubs/micropython,neilh10/micropython,aethaniel/micropython,rubencabrera/micropython,firstval/micropython,danicampora/micropython,cnoviello/micropython,danicampora/micropython,blazewicz/micropython,deshipu/micropython,pramasoul/micropython,dhylands/micropython,adafruit/circuitpython,EcmaXp/micropython,pozetroninc/micropython,galenhz/micropython,misterdanb/micropython,Vogtinator/micropython,ChuckM/micropython,ahotam/micropython,cwyark/micropython,mpalomer/micropython,swegener/micropython,redbear/micropython,utopiaprince/micropython,lbattraw/micropython,orionrobots/micropython,xuxiaoxin/micropython,rubencabrera/micropython,bvernoux/micropython,dhylands/micropython,emfcamp/micropython,galenhz/micropython,chrisdearman/micropython,trezor/micropython,martinribelotta/micropython,omtinez/micropython,slzatz/micropython,tobbad/micropython,noahwilliamsson/micropython,neilh10/micropython,torwag/micropython,AriZuu/micropython,xuxiaoxin/micropython,MrSurly/micropython,HenrikSolver/micropython,supergis/micropython,danicampora/micropython,blmorris/micropython,jimkmc/micropython,xyb/micropython,pramasoul/micropython,ahotam/micropython,noahchense/micropython,Peetz0r/micropython-esp32,skybird6672/micropython,henriknelson/micropython,redbear/micropython,utopiaprince/micropython,warner83/micropython,infinnovation/micropython,slzatz/micropython,pozetroninc/micropython,noahwilliamsson/micropython,paul-xxx/micropython,KISSMonX/micropython,aethaniel/micropython,jimkmc/micropython,chrisdearman/micropython,noahwilliamsson/micropython,methoxid/micropystat,pramasoul/micropython,xyb/micropython,blazewicz/micropython,trezor/micropython,pozetroninc/micropython,micropython/micropython-esp32,firstval/micropython,xuxiaoxin/micropython,omtinez/micropython,drrk/micropython,ernesto-g/micropython,jimkmc/micropython,vitiral/micropython,emfcamp/micropython,tdautc19841202/micropython,mhoffma/micropython,henriknelson/micropython,pramasoul/micropython,ruffy91/micropython,tdautc19841202/micropython,tdautc19841202/micropython,omtinez/micropython,ceramos/micropython,firstval/micropython,MrSurly/micropython-esp32,cloudformdesign/micropython,oopy/micropython,ryannathans/micropython,skybird6672/micropython,vriera/micropython,jlillest/micropython,dxxb/micropython,infinnovation/micropython,ahotam/micropython,drrk/micropython,warner83/micropython,alex-robbins/micropython,dxxb/micropython,chrisdearman/micropython,ruffy91/micropython,redbear/micropython,Timmenem/micropython,kerneltask/micropython,puuu/micropython,SungEun-Steve-Kim/test-mp,TDAbboud/micropython,misterdanb/micropython,warner83/micropython,xyb/micropython,pfalcon/micropython,Vogtinator/micropython,dinau/micropython,stonegithubs/micropython,pfalcon/micropython,suda/micropython,tobbad/micropython,infinnovation/micropython,hiway/micropython,blmorris/micropython,tralamazza/micropython,emfcamp/micropython,Vogtinator/micropython,adafruit/circuitpython,mgyenik/micropython,jimkmc/micropython,ryannathans/micropython,neilh10/micropython,Timmenem/micropython,orionrobots/micropython,suda/micropython,ceramos/micropython,misterdanb/micropython,alex-march/micropython,ericsnowcurrently/micropython,ericsnowcurrently/micropython,kostyll/micropython,ganshun666/micropython,MrSurly/micropython-esp32,pramasoul/micropython,PappaPeppar/micropython,deshipu/micropython,trezor/micropython,SungEun-Steve-Kim/test-mp,feilongfl/micropython,heisewangluo/micropython,toolmacher/micropython,lowRISC/micropython,torwag/micropython,adamkh/micropython,stonegithubs/micropython,alex-march/micropython,ericsnowcurrently/micropython,jmarcelino/pycom-micropython,danicampora/micropython,warner83/micropython,ganshun666/micropython,ericsnowcurrently/micropython,vriera/micropython,toolmacher/micropython,orionrobots/micropython,mgyenik/micropython,redbear/micropython,kerneltask/micropython,pfalcon/micropython,mgyenik/micropython,PappaPeppar/micropython,PappaPeppar/micropython,dmazzella/micropython,ceramos/micropython,xhat/micropython,selste/micropython,turbinenreiter/micropython,kerneltask/micropython,feilongfl/micropython,blmorris/micropython,mpalomer/micropython,heisewangluo/micropython,cloudformdesign/micropython,tralamazza/micropython,HenrikSolver/micropython,blazewicz/micropython,lowRISC/micropython,noahchense/micropython,praemdonck/micropython,chrisdearman/micropython,mianos/micropython,bvernoux/micropython,aethaniel/micropython,AriZuu/micropython,lbattraw/micropython,MrSurly/micropython,dhylands/micropython,paul-xxx/micropython,hosaka/micropython,hiway/micropython,dinau/micropython,jimkmc/micropython,EcmaXp/micropython,Vogtinator/micropython,kerneltask/micropython,Timmenem/micropython,vriera/micropython,ganshun666/micropython,ChuckM/micropython,Timmenem/micropython,skybird6672/micropython,stonegithubs/micropython,xyb/micropython,HenrikSolver/micropython,rubencabrera/micropython,pfalcon/micropython,puuu/micropython,noahchense/micropython,mgyenik/micropython,hosaka/micropython,SungEun-Steve-Kim/test-mp,adafruit/micropython,chrisdearman/micropython,jmarcelino/pycom-micropython,adafruit/circuitpython,ryannathans/micropython,infinnovation/micropython,alex-march/micropython,AriZuu/micropython,alex-robbins/micropython,hosaka/micropython,SHA2017-badge/micropython-esp32,vitiral/micropython,trezor/micropython,dhylands/micropython,matthewelse/micropython,mhoffma/micropython,xyb/micropython,martinribelotta/micropython,Peetz0r/micropython-esp32,bvernoux/micropython,oopy/micropython,lowRISC/micropython,tuc-osg/micropython,mianos/micropython,turbinenreiter/micropython,adafruit/circuitpython,skybird6672/micropython,supergis/micropython,xhat/micropython,HenrikSolver/micropython,firstval/micropython,alex-march/micropython,paul-xxx/micropython,MrSurly/micropython,noahwilliamsson/micropython,micropython/micropython-esp32,feilongfl/micropython,MrSurly/micropython,mhoffma/micropython,PappaPeppar/micropython,matthewelse/micropython,jlillest/micropython,swegener/micropython,heisewangluo/micropython,xhat/micropython,selste/micropython,ahotam/micropython,orionrobots/micropython,AriZuu/micropython,henriknelson/micropython,galenhz/micropython,xhat/micropython,supergis/micropython,omtinez/micropython,tralamazza/micropython,dhylands/micropython,hiway/micropython,toolmacher/micropython,hiway/micropython,mianos/micropython,praemdonck/micropython,cwyark/micropython,Vogtinator/micropython,mhoffma/micropython,lowRISC/micropython,selste/micropython,ruffy91/micropython,torwag/micropython,turbinenreiter/micropython,utopiaprince/micropython,ruffy91/micropython,supergis/micropython,alex-robbins/micropython,cnoviello/micropython,aethaniel/micropython,vitiral/micropython,turbinenreiter/micropython,aethaniel/micropython,adamkh/micropython,paul-xxx/micropython,misterdanb/micropython,ceramos/micropython,adamkh/micropython,tralamazza/micropython,mpalomer/micropython,matthewelse/micropython,cnoviello/micropython,blazewicz/micropython,martinribelotta/micropython,oopy/micropython,trezor/micropython,mianos/micropython,drrk/micropython,SHA2017-badge/micropython-esp32,ahotam/micropython,dinau/micropython,hiway/micropython,hosaka/micropython,ganshun666/micropython,jlillest/micropython,MrSurly/micropython-esp32,puuu/micropython,Peetz0r/micropython-esp32,kerneltask/micropython,EcmaXp/micropython,adafruit/micropython,vriera/micropython,lowRISC/micropython,redbear/micropython,deshipu/micropython,skybird6672/micropython,omtinez/micropython,tobbad/micropython,SHA2017-badge/micropython-esp32,heisewangluo/micropython,SHA2017-badge/micropython-esp32,jmarcelino/pycom-micropython,blazewicz/micropython,neilh10/micropython,adamkh/micropython,methoxid/micropystat,ruffy91/micropython,utopiaprince/micropython,paul-xxx/micropython,praemdonck/micropython,emfcamp/micropython,dmazzella/micropython,selste/micropython,misterdanb/micropython,noahwilliamsson/micropython,galenhz/micropython,MrSurly/micropython,oopy/micropython,jmarcelino/pycom-micropython,Peetz0r/micropython-esp32,vitiral/micropython,adamkh/micropython,ChuckM/micropython,ernesto-g/micropython,KISSMonX/micropython,praemdonck/micropython,toolmacher/micropython,utopiaprince/micropython,methoxid/micropystat,suda/micropython,vriera/micropython,tobbad/micropython,feilongfl/micropython,praemdonck/micropython,hosaka/micropython,kostyll/micropython,swegener/micropython,TDAbboud/micropython,dxxb/micropython,slzatz/micropython,dxxb/micropython,lbattraw/micropython,torwag/micropython,mianos/micropython,ericsnowcurrently/micropython,alex-march/micropython,MrSurly/micropython-esp32,bvernoux/micropython,cwyark/micropython,rubencabrera/micropython,xuxiaoxin/micropython,KISSMonX/micropython,swegener/micropython,TDAbboud/micropython,methoxid/micropystat,orionrobots/micropython,methoxid/micropystat,Peetz0r/micropython-esp32,matthewelse/micropython,cloudformdesign/micropython,selste/micropython,mpalomer/micropython,torwag/micropython,noahchense/micropython,blmorris/micropython,jmarcelino/pycom-micropython,SHA2017-badge/micropython-esp32,PappaPeppar/micropython,danicampora/micropython,SungEun-Steve-Kim/test-mp,TDAbboud/micropython,heisewangluo/micropython,vitiral/micropython,cloudformdesign/micropython,cwyark/micropython,emfcamp/micropython,EcmaXp/micropython,pfalcon/micropython,martinribelotta/micropython,tuc-osg/micropython,cloudformdesign/micropython,dinau/micropython,ceramos/micropython,neilh10/micropython,HenrikSolver/micropython,KISSMonX/micropython,ernesto-g/micropython