Fix comparisons in BandwidthTestHandler

This MR fixes the comparison page that produces wrong tables.

A preview of the fixed comparison page for the spruce_bandwidth test between lhcb-master.2219 and lhcb-master-mr.9664 (in lhcb/Moore!2746 (comment 7311219)) can be found here.

cc @rjhunter @lugrazet

requested review from @rjhunter and @lugrazet

assigned to @rjhunter and @lugrazet

approved this merge request

The new comparison page looks great @shunan - I'm happy to merge this unless there's anything more you wanted to do?

There's nothing else I want to do, @rjhunter please go ahead.

merged

mentioned in commit 08fd8ebb