RFR: 8260342: FXMLLoader fails to load a sub layout using fx:include with the resources attribute [v3]

[Guillaume Tâche]

> This fixes ResourceBundle loading by calling `ResourceBundle.getBundle(value, Locale.getDefault())` when the loader resources are null or their classloader is null.    
> Apparently the original author of the bug report said they would submit a pull request, but it seems like it never happened.

Guillaume Tâche has updated the pull request incrementally with one additional commit since the last revision:

  8260342: Resolve review comments

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Changes:
  - all: https://git.openjdk.org/jfx/pull/1158/files
  - new: https://git.openjdk.org/jfx/pull/1158/files/92da990d..0bc57bdd

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1158&range=02
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1158&range=01-02

  Stats: 4 lines in 1 file changed: 0 ins; 1 del; 3 mod
  Patch: https://git.openjdk.org/jfx/pull/1158.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1158/head:pull/1158

PR: https://git.openjdk.org/jfx/pull/1158