lttng: Add the link between the control flow view and the critical path

lttng: Add the link between the control flow view and the critical path

A parameter provider listens to the selection of the Control Flow View
and passes that selection as a parameter to the critical path analysis

Change-Id: I2866ffe27d715d76db6d401d97273a0020f25ab4
Signed-off-by: Francis Giraldeau <francis.giraldeau@gmail.com>
Signed-off-by: Geneviève Bastien <gbastien+lttng@versatic.net>
Reviewed-on: https://git.eclipse.org/r/41482
Reviewed-by: Hudson CI
Reviewed-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Tested-by: Matthew Khouzam <matthew.khouzam@ericsson.com>