Bug introduced in 583fa7d1e, KX_GameObject.setActionFrame can make BL_Action::m_starttime negative. But in BL_Action::Update m_starttime is set to the current time if it's negative.
To fix it we use a boolean BL_Action::m_initializedTime to know if we should initialize the time in BL_Action::Update, it's more stable than comparing times.
Tested with bug task T45945 and T32054, with an extra patch about to fix suspend resume scene issues with actions : D1569