Tests: Fix: test_list_triggers_cli: support in-kernel builtin lttng-modules

Tests: Fix: test_list_triggers_cli: support in-kernel builtin lttng-modules

This commit changes the grep call to remove the [lttng_tracer] string
from the pattern. When building the lttng modules directly in the kernel
there is not mention of [lttng_tracer].

Furthermore, the symbol type "t" is "T" in my test VM. The difference
may be due to the builtin nature of lttng on this VM.

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Change-Id: I046905dc51524c23ad3671b66614b86a084ef8e2
Depends-on: lttng-ust: If1f29dd64538bc5979d3e89aa5cca3be4e41046f