sink.text.pretty: remove field filtering

sink.text.pretty: remove field filtering

Field filtering uses GQuarks internally. Those generate g hash table
lookups, which appear at the top of perf reports.

This field filtering mechanism is not needed anymore, so remove it.

It's not needed anymore because the packet context fields and the event
fields are not special or associated to CTF anymore as the library's
trace IR is CTF-agnostic. So those special fields do not exist anyway in
the messages this sink consumes.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I7bf0238e6692fb277dafc32f864b0e20e89bf3d2
Reviewed-on: https://review.lttng.org/c/babeltrace/+/1505
CI-Build: Philippe Proulx <eeppeliteloop@gmail.com>
Reviewed-by: Philippe Proulx <eeppeliteloop@gmail.com>
Tested-by: jenkins <jenkins@lttng.org>