Add bt_common_abort() and use it instead of abort() directly

This patch adds bt_common_abort() which, for the moment, only calls
abort().

This patch also replaces all the calls to abort() with calls to
bt_common_abort().

The purpose is to control how all the parts of Babeltrace abort,
eventually adding other actions before calling abort() for example.

Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Change-Id: I2c8cd7ad760758041ef2dcaaa6b3ef84f89d80e6
Reviewed-on: https://review.lttng.org/c/babeltrace/+/2317
Tested-by: jenkins <jenkins@lttng.org>