Emacs did that for a long time, then both Emacs and XEmacs shifted to a more explicit serialization mechanism (the resulting files are mmap()ed in, so still shared between instances IIRC), mostly because keeping unexec() working was a pain.
LaTeX never did the coredump trick because it wasn't originally written on a Unix system at all (hell, it's written in Pascal). It's always written out a serialized representation of its state ('format files') then loaded them later. I'm not sure how valuable this is for LaTeX proper anymore (who cares about a fraction of a second?) but it's very valuable for big formats like ConTeXt, which takes ages to load even on modern systems.