Using sys.exit() with no arguments causes TypeError inside ptvsd

[huguesv]

Environment data

• PTVSD version: 4.1.3
• OS and version: Windows 10
• Python version (& distribution if applicable, e.g. Anaconda): 3.6
• Using VS Code or Visual Studio: VS

Actual behavior

During handling of the above exception, another exception occurred:
Traceback (most recent call last):
  File "c:\program files (x86)\microsoft visual studio\2017\community\common7\ide\extensions\microsoft\python\core\ptvsd_launcher.py", line 119, in <module>
    
vspd.debug(filename, port_num, debug_id, debug_options, run_as)

  File "c:\program files (x86)\microsoft visual studio\2017\community\common7\ide\extensions\microsoft\python\core\Packages\ptvsd\debugger.py", line 37, in debug
    
run(address, filename, *args, **kwargs)

  File "c:\program files (x86)\microsoft visual studio\2017\community\common7\ide\extensions\microsoft\python\core\Packages\ptvsd\_local.py", line 48, in run_file
    
run(argv, addr, **kwargs)

  File "c:\program files (x86)\microsoft visual studio\2017\community\common7\ide\extensions\microsoft\python\core\Packages\ptvsd\_local.py", line 101, in _run
    
daemon.exitcode = int(ex.code)

TypeError
: 
int() argument must be a string, a bytes-like object or a number, not 'NoneType'

Expected behavior

No error

Steps to reproduce:

1. Debug this code:

sys.exit()

https://docs.python.org/3/library/sys.html#sys.exit