tests/run-tests: Disable thread/stress_heap.py when running on Travis.
tests/run-tests: Disable thread/stress_heap.py when running on Travis.

It has reliability issues and sometimes fails on Travis (reason currently
unknown).

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