[jfx19] RFR: 8290331 Binding value left null when immediately revalidated in invalidation listener [v2]

[John Hendrikx]

> I introduced a bug with the fluent bindings PR which affects all ObjectBindings.
> 
> This is the code that fails:
> 
>         SimpleObjectProperty<Boolean> condition = new SimpleObjectProperty<>(true);
>         ObservableValue<String> binding = condition.map(Object::toString);
> 
>         binding.addListener(o -> { binding.getValue(); });
> 
>         condition.set(false);
> 
>         assertEquals(false, binding.getValue());  // returns null (!)
> 
> This PR fixes this problem and adds a test case to cover it.

John Hendrikx has updated the pull request incrementally with one additional commit since the last revision:

  Change explanatory comment to block comment

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

Changes:
  - all: https://git.openjdk.org/jfx/pull/829/files
  - new: https://git.openjdk.org/jfx/pull/829/files/4c8453af..34856569

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=829&range=01
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=829&range=00-01

  Stats: 7 lines in 1 file changed: 5 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jfx/pull/829.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/829/head:pull/829

PR: https://git.openjdk.org/jfx/pull/829