py/lexer: Remove unnecessary code, and unreachable code.
py/lexer: Remove unnecessary code, and unreachable code.

Setting emit_dent=0 is unnecessary because arriving in that part of the
if-logic will guarantee that emit_dent is already zero.

The block to check indent_top(lex)>0 is unreachable because a newline is
always inserted an the end of the input stream, and hence dedents are
always processed before EOF.

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