XML state system: Add support of different comparison operators to the XML.

XML state system: Add support of different comparison operators to the XML.

This will add 6 new comparison operators to the xml conditional statements.
These operators are: eq, ne, ge, gt, le, lt.

Change-Id: Ice9e87503eec6fea5a5d2281ffd8e42e59c8224a
Signed-off-by: Naser Ezzati <n.ezzati@polymtl.ca>
Reviewed-on: https://git.eclipse.org/r/35681
Tested-by: Hudson CI
Reviewed-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Reviewed-by: Genevieve Bastien <gbastien+lttng@versatic.net>
Tested-by: Genevieve Bastien <gbastien+lttng@versatic.net>