tmf: Preserve order of marker categories

tmf: Preserve order of marker categories

Some marker event sources can have a logical order to the list of marker
categories they return in IMarkerEventSource.getMarkerCategories(). This
order should be preserved, so the categories should not be sorted
alphabetically.

Change-Id: I0423b391271fdd0803aba6bd357d7482938aad4b
Signed-off-by: Patrick Tasse <patrick.tasse@gmail.com>
Reviewed-on: https://git.eclipse.org/r/66541
Reviewed-by: Hudson CI
Tested-by: Bernd Hufmann <bernd.hufmann@ericsson.com>
Reviewed-by: Bernd Hufmann <bernd.hufmann@ericsson.com>