Ecore internally uses 10 events, from ECORE_EVENT_SIGNAL_USER=1 to
ECORE_EVENT_SYSTEM_TIMEDATE_CHANGED=10. The Ecore.Event.Message_Handler
singleton that holds the counter of events is initialized with -1.
This is followed in _ecore_event_init() by ten calls to
ecore_event_message_handler_type_new(), which increase the counter of
event by one each.

This results in an event counter to be 9 (-1 + 10) at the end of the
initialization of ecore_events. This means that the next event to be
created will have a value of 10, which will overlap with
ECORE_EVENT_SYSTEM_TIMEDATE_CHANGED. As such, these two distinct events
will be aliased and their associated handlers will be called at
unexpected times, with unexpected data.

By changing the constructor value from -1 to 0, we prevent this event
aliasing.

Fixes T6605