py/objint: In int.from_bytes, only create big-int if really needed.
py/objint: In int.from_bytes, only create big-int if really needed.

This patch ensures that int.from_bytes only creates a big-int if necessary,
by checking the value for a small-int overflow as it's being parsed.

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