py/qstr: Change type of qstr from mp_uint_t to size_t.
py/qstr: Change type of qstr from mp_uint_t to size_t.

For builds where mp_uint_t is larger than size_t, it doesn't make
sense to use such a wide type for qstrs.  There can only be as many
qstrs as there is address space on the machine, so size_t is the correct
type to use.

Saves about 3000 bytes of code size when building unix/ port with
MICROPY_OBJ_REPR_D.

bvernoux/micropython,toolmacher/micropython,adafruit/circuitpython,adafruit/micropython,micropython/micropython-esp32,mhoffma/micropython,tuc-osg/micropython,deshipu/micropython,puuu/micropython,micropython/micropython-esp32,dmazzella/micropython,ganshun666/micropython,cwyark/micropython,misterdanb/micropython,redbear/micropython,tuc-osg/micropython,MrSurly/micropython-esp32,TDAbboud/micropython,ernesto-g/micropython,puuu/micropython,dinau/micropython,SHA2017-badge/micropython-esp32,swegener/micropython,infinnovation/micropython,infinnovation/micropython,cwyark/micropython,mpalomer/micropython,matthewelse/micropython,adafruit/micropython,pozetroninc/micropython,dxxb/micropython,adafruit/micropython,henriknelson/micropython,deshipu/micropython,mpalomer/micropython,Peetz0r/micropython-esp32,chrisdearman/micropython,jmarcelino/pycom-micropython,Timmenem/micropython,tralamazza/micropython,chrisdearman/micropython,ganshun666/micropython,turbinenreiter/micropython,cwyark/micropython,TDAbboud/micropython,TDAbboud/micropython,lowRISC/micropython,praemdonck/micropython,EcmaXp/micropython,chrisdearman/micropython,swegener/micropython,ernesto-g/micropython,toolmacher/micropython,SHA2017-badge/micropython-esp32,MrSurly/micropython,tralamazza/micropython,dinau/micropython,matthewelse/micropython,torwag/micropython,martinribelotta/micropython,adafruit/circuitpython,dxxb/micropython,danicampora/micropython,blazewicz/micropython,dxxb/micropython,SHA2017-badge/micropython-esp32,mpalomer/micropython,redbear/micropython,adafruit/circuitpython,torwag/micropython,deshipu/micropython,redbear/micropython,trezor/micropython,infinnovation/micropython,praemdonck/micropython,mhoffma/micropython,TDAbboud/micropython,MrSurly/micropython,galenhz/micropython,praemdonck/micropython,jmarcelino/pycom-micropython,mianos/micropython,pramasoul/micropython,pramasoul/micropython,micropython/micropython-esp32,trezor/micropython,supergis/micropython,infinnovation/micropython,PappaPeppar/micropython,cwyark/micropython,bvernoux/micropython,pozetroninc/micropython,ryannathans/micropython,emfcamp/micropython,pozetroninc/micropython,emfcamp/micropython,dmazzella/micropython,hiway/micropython,danicampora/micropython,mhoffma/micropython,turbinenreiter/micropython,danicampora/micropython,lowRISC/micropython,adamkh/micropython,Peetz0r/micropython-esp32,SHA2017-badge/micropython-esp32,trezor/micropython,martinribelotta/micropython,alex-march/micropython,swegener/micropython,bvernoux/micropython,Peetz0r/micropython-esp32,PappaPeppar/micropython,PappaPeppar/micropython,mianos/micropython,hosaka/micropython,pozetroninc/micropython,MrSurly/micropython,Timmenem/micropython,alex-march/micropython,EcmaXp/micropython,ernesto-g/micropython,mhoffma/micropython,jmarcelino/pycom-micropython,trezor/micropython,kerneltask/micropython,swegener/micropython,puuu/micropython,kerneltask/micropython,MrSurly/micropython-esp32,turbinenreiter/micropython,alex-robbins/micropython,emfcamp/micropython,jmarcelino/pycom-micropython,danicampora/micropython,HenrikSolver/micropython,adafruit/circuitpython,TDAbboud/micropython,hosaka/micropython,tobbad/micropython,henriknelson/micropython,ryannathans/micropython,hosaka/micropython,ryannathans/micropython,supergis/micropython,alex-march/micropython,Peetz0r/micropython-esp32,alex-robbins/micropython,blazewicz/micropython,swegener/micropython,pfalcon/micropython,turbinenreiter/micropython,galenhz/micropython,dxxb/micropython,tuc-osg/micropython,tralamazza/micropython,drrk/micropython,ryannathans/micropython,pfalcon/micropython,supergis/micropython,tralamazza/micropython,ernesto-g/micropython,HenrikSolver/micropython,martinribelotta/micropython,mianos/micropython,EcmaXp/micropython,pozetroninc/micropython,galenhz/micropython,adafruit/micropython,pramasoul/micropython,adafruit/circuitpython,pramasoul/micropython,SHA2017-badge/micropython-esp32,ganshun666/micropython,Peetz0r/micropython-esp32,dinau/micropython,dmazzella/micropython,misterdanb/micropython,chrisdearman/micropython,tuc-osg/micropython,toolmacher/micropython,torwag/micropython,HenrikSolver/micropython,matthewelse/micropython,hiway/micropython,mpalomer/micropython,ernesto-g/micropython,lowRISC/micropython,dinau/micropython,redbear/micropython,alex-march/micropython,selste/micropython,matthewelse/micropython,torwag/micropython,alex-robbins/micropython,henriknelson/micropython,PappaPeppar/micropython,drrk/micropython,EcmaXp/micropython,matthewelse/micropython,AriZuu/micropython,tobbad/micropython,HenrikSolver/micropython,dinau/micropython,hosaka/micropython,emfcamp/micropython,misterdanb/micropython,blazewicz/micropython,alex-robbins/micropython,deshipu/micropython,pfalcon/micropython,bvernoux/micropython,misterdanb/micropython,supergis/micropython,blazewicz/micropython,alex-robbins/micropython,PappaPeppar/micropython,AriZuu/micropython,trezor/micropython,adafruit/micropython,oopy/micropython,jmarcelino/pycom-micropython,dxxb/micropython,ganshun666/micropython,Timmenem/micropython,AriZuu/micropython,HenrikSolver/micropython,MrSurly/micropython-esp32,tobbad/micropython,selste/micropython,blazewicz/micropython,galenhz/micropython,martinribelotta/micropython,oopy/micropython,torwag/micropython,MrSurly/micropython,oopy/micropython,Timmenem/micropython,micropython/micropython-esp32,puuu/micropython,hiway/micropython,toolmacher/micropython,puuu/micropython,ryannathans/micropython,EcmaXp/micropython,AriZuu/micropython,kerneltask/micropython,martinribelotta/micropython,chrisdearman/micropython,hiway/micropython,selste/micropython,deshipu/micropython,mpalomer/micropython,galenhz/micropython,MrSurly/micropython-esp32,infinnovation/micropython,hiway/micropython,mhoffma/micropython,pfalcon/micropython,henriknelson/micropython,pramasoul/micropython,supergis/micropython,tuc-osg/micropython,danicampora/micropython,adamkh/micropython,kerneltask/micropython,drrk/micropython,henriknelson/micropython,drrk/micropython,adafruit/circuitpython,MrSurly/micropython-esp32,MrSurly/micropython,micropython/micropython-esp32,alex-march/micropython,oopy/micropython,cwyark/micropython,dmazzella/micropython,mianos/micropython,misterdanb/micropython,tobbad/micropython,bvernoux/micropython,praemdonck/micropython,adamkh/micropython,adamkh/micropython,lowRISC/micropython,redbear/micropython,oopy/micropython,selste/micropython,ganshun666/micropython,hosaka/micropython,drrk/micropython,emfcamp/micropython,lowRISC/micropython,toolmacher/micropython,praemdonck/micropython,kerneltask/micropython,adamkh/micropython,turbinenreiter/micropython,AriZuu/micropython,pfalcon/micropython,selste/micropython,Timmenem/micropython,mianos/micropython,tobbad/micropython,matthewelse/micropython