ctf.core: making some classes final

ctf.core: making some classes final

This patch is to make some classes final in ctf.core component.
It should be final to improve readability and since you should never
extend it. It also allows the jvm to inline methods and improve performance.

Change-Id: I6e9bef701898716978c6e7b4b20254eabc8cd6c8
Signed-off-by: Wassim <wassim.nasrallah.36@gmail.com>
Reviewed-on: https://git.eclipse.org/r/73771
Reviewed-by: Hudson CI
Reviewed-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Tested-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Reviewed-by: Genevieve Bastien <gbastien+lttng@versatic.net>
Tested-by: Genevieve Bastien <gbastien+lttng@versatic.net>