tmf: Fix selectAndReveal() in timegraphViewer

tmf: Fix selectAndReveal() in timegraphViewer

This fix handles the selectAndReveal() as if it came from an internal
source (triggered by the user) since the method is called from the
FindDialog. The selection should not be ignored when a pending selection
change is awaiting to be notified.

Change-Id: I1be75843b3fcb463eefa2c7587226205424b9c62
Signed-off-by: Jean-Christian Kouame <jean-christian.kouame@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/71484
Reviewed-by: Hudson CI
Reviewed-by: Patrick Tasse <patrick.tasse@gmail.com>
Tested-by: Patrick Tasse <patrick.tasse@gmail.com>