RFR: 8342462: TextAreaSkin: remove USE_MULTIPLE_NODES

[Kevin Rushforth]

On Wed, 16 Oct 2024 23:01:39 GMT, Andy Goryachev <angorya at openjdk.org> wrote:

> Removed "not yet fully implemented" USE_MULTIPLE_NODES and related code.
> 
> I would like to remove the early unfinished idea of using multiple Text nodes in TextAreaSkin to clean up the code, to make it easier to do fixes for [JDK-8342233](https://bugs.openjdk.org/browse/JDK-8342233) and [JDK-8296266](https://bugs.openjdk.org/browse/JDK-8296266).
> 
> Also some minor cleanup.
> 
> ## Summary of Changes
> 
> - removed USE_MULTIPLE_NODES and code paths that correspond to its `true` value
> - permanently adding one Text node to `paragraphNodes` Group, keeping the latter for compatibility purposes
> - removed any code that scans `paragraphNodes` children
> - using `getTextNode()` in place of `((Text)paragraphNodes.getChildren().get(0))`

Either @arapte or I will review this. I think a single reviewer will be enough, given that the functionality hasn't changed.

-------------

PR Comment: https://git.openjdk.org/jfx/pull/1601#issuecomment-2423935739