timing: add statistics analysis to functions calls

timing: add statistics analysis to functions calls

This, with the flame graph, call stack, call graph and function densisty
can make a profiling perspective.

Additional tests coming in a separate patch.

Change-Id: Idcee650cf9b32963b5aaddd3e66a8d00e06b5b9e
Signed-off-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/79898
Reviewed-by: Hudson CI
Reviewed-by: Genevieve Bastien <gbastien+lttng@versatic.net>
Tested-by: Genevieve Bastien <gbastien+lttng@versatic.net>