RFR: 8273138: BidirectionalBinding fails to observe changes of invalid properties

[Michael Strauß]

This PR fixes a bug that was introduced in #454.

Since this fix might impact the performance considerations in the original PR, I ran a performance benchmark against the previous `ChangeListener`-based implementation, which still shows better performance for the new implementation:


@State(Scope.Benchmark)
public class BindingBenchmark {
    DoubleProperty property1 = new SimpleDoubleProperty();
    DoubleProperty property2 = new SimpleDoubleProperty();

    public BindingBenchmark() {
        property2.bindBidirectional(property1);
    }

    @Benchmark
    public void benchmark() {
        for (int i = 0; i < 10000000; ++i) {
            property1.set((i % 2 == 0) ? 12345.0 : 54321.0);
        }
    }
}


| Benchmark | Mode | Cnt | Score | Error | Units |
|-----------|------|-----|-------|-------|--------|
| ChangeListener | thrpt | 5 | 7.463 | 0.040 | ops/s |
| InvalidationListener (fixed) | thrpt | 5 | 15.095 | 0.092 | ops/s |

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

Commit messages:
 - fixed invalidation bug
 - added failing test

Changes: https://git.openjdk.java.net/jfx/pull/614/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jfx&pr=614&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8273138
  Stats: 54 lines in 2 files changed: 54 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jfx/pull/614.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/614/head:pull/614

PR: https://git.openjdk.java.net/jfx/pull/614