[lldb/Target] Fix event handling during process launch

This patch fixes process event handling when the events are broadcasted
at launch. To do so, the patch introduces a new listener to fetch events
by hand off the event queue and then resending them ensure the event ordering.

Differental Revision: https://reviews.llvm.org/D105698



Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>