py/runtime: Optimise case of identity iterator so it doesn't alloc RAM.
py/runtime: Optimise case of identity iterator so it doesn't alloc RAM.

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