Check all ancestor namespace transitions when rendering raw text in html in golang.org/x/net

In childTextNodesAreLiteral, walking up the tree previously stopped at the nearest foreign ancestor once an HTML integration point was found. However, that integration point may itself be a descendant of an element that was foster-parented into a foreign namespace (such as or fostered under ), causing a parser to resolve the subtree in a different foreign namespace upon re-parsing the rendered output.

Continue walking the full ancestor chain and verify that every transition from a non-empty namespace occurs at an HTML integration point before emitting literal text.