RFR: 8243115: Unregister bindings when unbind called multiple times

[Kevin Rushforth]

On Mon, 27 Apr 2020 13:13:44 GMT, Kevin Rushforth <kcr at openjdk.org> wrote:

>> This fixes a bug where the first call to unbind would clear the internal invalidation listener used, resulting in
>> subsequent unbind calls to be no-ops, unless bind was called again first.
>> I had to rewrite the parameterized test slightly as Parameterized will only call the parameters method once, and my new
>> test modifies the internal state of the bindings used as parameters (by doing some unbind calls) which was making other
>> tests fail.
>
> The title of this PR should match exactly the title of the JBS bug. So:
> 
> 8243115: Spurious invalidations due to bug in IntegerBinding and other classes

@arapte can you also review this?

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PR: https://git.openjdk.java.net/jfx/pull/198