I don't know, and it'd take some doing (money incentives, etc.) to arrange for some kind of comprehensive testing 'bout that
But who'd you hear that from, about the Caravelle, and 752. I imagine any of the older and/or lower-cruising speed airliners glide the best, just from better lift from the less-swept-back wings. I reckon the Dornier 328 Jet would glide pretty darn well, for instance.
(and then of course there are all the turboprops to consider. You mention "airliner" so I'm not sure if you're excluding 'em entirely)