JSDoc: JSTypeExpression#getRoot() nodes have random source locations

`JsDocInfoParser` provides random source positions for `JSTypeExpressions` in various JSDoc tags (most often, the position of the following token is used,) and this varies across kinds of parsed types. One point is that `JsDocInfoParser#wrapNode(int, Node)` uses the current stream position, not the Node's position.

On a related note, `JsDocTokenStream#ungetChar()` does not rewind the `charno` value along with `cursor`, which seems to contribute to this issue.