XML state system: Add "eventName" to the current stateattribute types.

We already have the "eventName" as a type for statevalue, but sometimes we need
it as a valid stateattribute type as well, e.g., in counting the number of each
event type.

Change-Id: Ie699221d71cee1686c6865bcffc3b38a991a0731
Signed-off-by: Naser Ezzati <n.ezzati@polymtl.ca>
Reviewed-on: https://git.eclipse.org/r/36059
Tested-by: Hudson CI
Reviewed-by: Genevieve Bastien <gbastien+lttng@versatic.net>
Tested-by: Genevieve Bastien <gbastien+lttng@versatic.net>
tmf: Consolidate constructors in TmfEvent

The default constructor can be used by the ITmfEvent extension
point, so should remain available, but should not be used by
normal code.

Change-Id: Id0e5e6d35d5593852b2a89672efea4fcbcd5b948
Signed-off-by: Alexandre Montplaisir <alexmonthy@voxpopuli.im>
Reviewed-on: https://git.eclipse.org/r/36130
Tested-by: Hudson CI
Reviewed-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
tmf: Add missing NonNull import to tmf.ui.tests

Change-Id: Iec621cb9eb70773e71433ebb7498d6329d7842ef
Signed-off-by: Alexandre Montplaisir <alexmonthy@voxpopuli.im>
Reviewed-on: https://git.eclipse.org/r/36374
Tested-by: Hudson CI
Reviewed-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>
Tested-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>