All whitespace remains meaningless. That is, the optional closing tag has nothing to do with a newline. Rather, they are defined as optional if the next tag is one of a set, or their parent is closed.

https://html.spec.whatwg.org/multipage/syntax.html#optional-... is where these are defined. It basically says that a TD remains open until the next sibling td or the tr/tbody/table that it is in is closed.