Revert take_execution_state to the 6.17 version.

This is intended to fix problems caused by the changes outside of
screens.
sl2: Do not take state from predicted displayables or transforms.

If the parameters to a displayable or transform change between
when a screen is predicted and when it is shown, it means that
the prediction was incorrect.

We now discard the incorrect prediction state, instead of allowing it
to influence the screen.

See: http://lemmasoft.renai.us/forums/ucp.php?i=pm&mode=view&f=0&p=144880
See: http://lemmasoft.renai.us/forums/viewtopic.php?p=338394#p338394