py/builtinimport: Support importing packages from compiled .mpy files.
py/builtinimport: Support importing packages from compiled .mpy files.

This patch ensures that __init__.mpy files are imported if their
containing directory is imported as a package.

MrSurly/micropython,chrisdearman/micropython,TDAbboud/micropython,kerneltask/micropython,toolmacher/micropython,trezor/micropython,ryannathans/micropython,trezor/micropython,chrisdearman/micropython,hiway/micropython,swegener/micropython,HenrikSolver/micropython,AriZuu/micropython,selste/micropython,Peetz0r/micropython-esp32,blazewicz/micropython,dmazzella/micropython,kerneltask/micropython,Peetz0r/micropython-esp32,mhoffma/micropython,deshipu/micropython,pramasoul/micropython,pfalcon/micropython,lowRISC/micropython,torwag/micropython,HenrikSolver/micropython,henriknelson/micropython,dmazzella/micropython,torwag/micropython,blazewicz/micropython,ryannathans/micropython,tuc-osg/micropython,tobbad/micropython,dmazzella/micropython,bvernoux/micropython,henriknelson/micropython,tobbad/micropython,bvernoux/micropython,mhoffma/micropython,oopy/micropython,AriZuu/micropython,mhoffma/micropython,TDAbboud/micropython,toolmacher/micropython,HenrikSolver/micropython,tobbad/micropython,pozetroninc/micropython,tralamazza/micropython,micropython/micropython-esp32,pramasoul/micropython,adafruit/micropython,puuu/micropython,TDAbboud/micropython,alex-robbins/micropython,Timmenem/micropython,lowRISC/micropython,tralamazza/micropython,trezor/micropython,alex-robbins/micropython,cwyark/micropython,henriknelson/micropython,bvernoux/micropython,chrisdearman/micropython,hiway/micropython,PappaPeppar/micropython,micropython/micropython-esp32,mhoffma/micropython,puuu/micropython,MrSurly/micropython,adafruit/circuitpython,SHA2017-badge/micropython-esp32,tralamazza/micropython,selste/micropython,AriZuu/micropython,lowRISC/micropython,pramasoul/micropython,tobbad/micropython,kerneltask/micropython,ryannathans/micropython,PappaPeppar/micropython,torwag/micropython,Peetz0r/micropython-esp32,pfalcon/micropython,infinnovation/micropython,pramasoul/micropython,Peetz0r/micropython-esp32,SHA2017-badge/micropython-esp32,chrisdearman/micropython,puuu/micropython,pramasoul/micropython,dmazzella/micropython,adafruit/circuitpython,HenrikSolver/micropython,tuc-osg/micropython,MrSurly/micropython-esp32,lowRISC/micropython,adafruit/circuitpython,blazewicz/micropython,mhoffma/micropython,MrSurly/micropython-esp32,infinnovation/micropython,adafruit/micropython,henriknelson/micropython,deshipu/micropython,henriknelson/micropython,kerneltask/micropython,hiway/micropython,oopy/micropython,Timmenem/micropython,HenrikSolver/micropython,pozetroninc/micropython,pozetroninc/micropython,torwag/micropython,adafruit/micropython,selste/micropython,alex-robbins/micropython,chrisdearman/micropython,PappaPeppar/micropython,TDAbboud/micropython,AriZuu/micropython,MrSurly/micropython,adafruit/circuitpython,ryannathans/micropython,adafruit/micropython,swegener/micropython,tralamazza/micropython,pozetroninc/micropython,toolmacher/micropython,SHA2017-badge/micropython-esp32,PappaPeppar/micropython,infinnovation/micropython,MrSurly/micropython-esp32,infinnovation/micropython,MrSurly/micropython-esp32,puuu/micropython,torwag/micropython,pfalcon/micropython,infinnovation/micropython,tuc-osg/micropython,puuu/micropython,adafruit/micropython,TDAbboud/micropython,cwyark/micropython,hiway/micropython,MrSurly/micropython,swegener/micropython,pfalcon/micropython,selste/micropython,PappaPeppar/micropython,hiway/micropython,alex-robbins/micropython,oopy/micropython,deshipu/micropython,cwyark/micropython,alex-robbins/micropython,Peetz0r/micropython-esp32,blazewicz/micropython,kerneltask/micropython,deshipu/micropython,bvernoux/micropython,adafruit/circuitpython,micropython/micropython-esp32,trezor/micropython,adafruit/circuitpython,trezor/micropython,ryannathans/micropython,swegener/micropython,tuc-osg/micropython,swegener/micropython,SHA2017-badge/micropython-esp32,oopy/micropython,selste/micropython,tobbad/micropython,blazewicz/micropython,MrSurly/micropython,AriZuu/micropython,cwyark/micropython,micropython/micropython-esp32,lowRISC/micropython,toolmacher/micropython,Timmenem/micropython,pfalcon/micropython,pozetroninc/micropython,Timmenem/micropython,toolmacher/micropython,micropython/micropython-esp32,Timmenem/micropython,MrSurly/micropython-esp32,tuc-osg/micropython,SHA2017-badge/micropython-esp32,bvernoux/micropython,deshipu/micropython,oopy/micropython,cwyark/micropython