Adds a heuristic to avoid exiting after a recent warping to VBMC._check_termination_conditions() (same check as exists in MATLAB version, but it wasn't present in Python).
Removes the assignment of success_flag from VBMC._check_termination_condition(), since the flag is reset based on VP stability at the end of the VBMC main loop.
VBMC._check_termination_conditions()
(same check as exists in MATLAB version, but it wasn't present in Python).success_flag
fromVBMC._check_termination_condition()
, since the flag is reset based on VP stability at the end of the VBMC main loop.