BandwidthTestHandler: Finish the job on fixing the comparison page
I'm sorry folks, I didn't quite complete the job with the last patch, I was rushing too much. I scrutinized the comparison pages a little more: my last patch should make them build (and people should be getting messages back on their MRs) but the per-line comparisons still weren't quite right, and I think they might not show up on the pages. After a bit more work I get per-line differences back in my local tests with these changes.