Draw: continues to draw after window flipped

[RebeccaHirst]

Locally in PsychoPy calling .draw() will draw when the findo is flipped but stop drawing on the next frame.

i.e.

polygon.draw()
win.flip()

would show the polygon, but:

polygon.draw()
win.flip()
win.flip()

would not show the polygon.

In PsychoJS this behaves differently, the polygon will continue to draw even after additional window flips. To avoid this, we need us use setAutoDraw(True) and setAutoDraw(False) which is ok but might be nexpected behaviour for many.

Minimal bug demo here: https://gitlab.pavlovia.org/Consultancy/draw_bug