builtinimport: Fix running package submodule with -m.
builtinimport: Fix running package submodule with -m.

When "micropython -m pkg.mod" command was used, relative imports in pkg.mod
didn't work, because pkg.mod.__name__ was set to __main__, and the fact that
it's a package submodule was missed. This is an original workaround to this
issue. TODO: investigate and compare how CPython deals with this issue.

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