https://jakob.engbloms.se/archives/1564
The Green Hills Software Time Machine product for time travel debugging was commercially available by September 2003 [1] which is at least contemporaneous with that paper by Bill Lewis (i.e. terminology could not have been derived from it).
Given the alternative terminology frequently used for the technology up to and after that point such as bidirectional, reverse, reversible, omniscient, replay, record-replay, etc. time-travel debugging as a term almost certainly originates/was popularized by Time Machine as the first successful time travel product (yes, I see the Lauterbach CTS is listed as existing first, but it was not commercially distinguished and successful and obviously has no terminology lineage).
Unless you mean something really narrow like clicking a variable and it showing you every previous value of it in one screen? I am not sure if it has that built-in. But really that is just visualization layer stuff. The recorded log has everything you need to reconstruct every past state, so you can get anything missing from the built-ins by just querying the log directly.
https://arxiv.org/abs/cs/0310016
https://www.youtube.com/watch?v=xpI8hIgOyko
Soon later, "debugging backwards in time" morphed into "time-travel debugging"