This function is tightly coupled to the state and behaviour of the
scheduler, and is a core part of the runtime: to schedule a pending
exception. So move it there.
Previous behaviour is when this argument is set to "true", in which case
the function will raise any pending exception. Setting it to "false" will
cancel any pending exception.
Behaviour was changed from stack to queue in
8977c7eb58, and this updates variable names
to match. Also updates other references (docs, error messages).
Damien George
Jim Mussared
Andrew Leech