I think I'd suggest omitting the \vtop if LOC is set to some new value, like "longfloat". If table material was ever actually floated, including "here", it would need to be in a vbox since it should not be split across pages, as Gavin already pointed out.
Actually doing something sensible with a multi-page table is a much bigger problem (repeating headers, what to do with the caption, etc.). I know that's not Arnold's immediate problem, but looking ahead, I could imagine having makeinfo --latex use one of the longtable packages in the event of a long float. (Implementing it in texinfo.tex would not be sensible IMHO.) I think the best package for that nowadays is xltabular (https://ctan.org/pkg/xltabular), but which LaTeX package gets loaded should presumably be configurable. Happy Texinfoing, Karl
