Tests: triggers: Add syscall event rule condition filter tests

Tests: triggers: Add syscall event rule condition filter tests

This test has limited value as it's impossible to distinguish events
from buggy filtering from the ones that went through the filter
successfully.

Keep that test case anyway, as it exercises those code paths.

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: I1b1f9ecb29b7e09b4b8f66034e8911a645aabe3c
Depends-on: lttng-ust: I5a800fc92e588c2a6a0e26282b0ad5f31c044479