allow pausing of code in the event loop

[bdieterm]

I have removed a restriction for pausing executed code so that gui event loops can also be paused.

Code for testing:

import time
import os

if __pyzo__.guiName == 'PYSIDE6':

    os.environ['PYZO_PROCESS_EVENTS_WHILE_DEBUGGING'] = '0'

    from PySide6 import QtGui, QtCore, QtWidgets

    cnt = 0
    def callback_timer():
        global cnt
        print('event loop', cnt)
        cnt += 1
        if cnt > 10:
            my_timer.stop()
            print('finished')

    my_timer = QtCore.QTimer()
    my_timer.timeout.connect(callback_timer)
    my_timer.start(500)

elif __pyzo__.guiName == 'ASYNCIO':

    import asyncio

    def bar():
        for cnt in range(10):
            print('event loop', cnt)
            time.sleep(0.5)
        print('finished')

    loop = asyncio.get_running_loop()
    loop.call_soon(bar)


print('press pause now to interrupt regular script')
for a in range(10):
    print(chr(ord('a') + a))
    time.sleep(0.5)

print('press pause now to interrupt event loop stuff')

Note that, after merging this commit, "Pause" can be activated even when running no code at all. But in that case, it does not matter if the user then continues or stops execution in the debugger mode.

For the given example, I have seen that pausing in asyncio event loops mostly stops in the user's code, and sometimes in Python's asyncio library. Pausing in PySide6 event loops mostly stops in Pyzo's yoton library.