Changes

tmf: Bug 579997: Incorrect item bounds in time graph

Consider the top index bounds in item bounds calculation.

Also fix the ySums cache size.

Change-Id: Icf3d66364486cb9a1af2b2012a81e71d5316d746
Signed-off-by: Patrick Tasse <patrick.tasse@gmail.com>
Reviewed-on: https://git.eclipse.org/r/c/tracecompass/org.eclipse.tracecompass/+/193592
Tested-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Tested-by: Trace Compass Bot <tracecompass-bot@eclipse.org>
Reviewed-by: Matthew Khouzam <matthew.khouzam@ericsson.com>