[ty] fix GotoTargets for keyword args in nested function calls (#20013)
While implementing similar logic for initializers I noticed that this
code appeared to be walking the ancestors in the wrong direction, and so
if you have nested function calls it would always grab the outermost one
instead of the closest-ancestor.
The four copies of the test are because there's something really evil in
our caching that can't seem to be demonstrated in our cursor testing
framework, which I'm filing a followup for.