Changes

weighted tree: Add the ability to differentiate 2 treesets

Also the IWeightedTreeSet#getTreesFor(E) method changed parameter type
to Object as some elements may change type for example in differential
tree providers or when grouped by, so the set may not contain trees only
for E object, or the type is not correctly followed by the compiler
which gives warnings all over the place otherwise.

[added] Ability to differentiate 2 treesets
[changed] IWeightedTreeSet#getTreesFor(E), E changed to Object

Change-Id: I9874011aeeeee2d9a6151381f85700eddc3cd25f
Signed-off-by: Geneviève Bastien <gbastien+lttng@versatic.net>
Reviewed-on: https://git.eclipse.org/r/153518
Tested-by: Trace Compass Bot <tracecompass-bot@eclipse.org>
Reviewed-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Tested-by: Matthew Khouzam <matthew.khouzam@ericsson.com>