ProgressBar has significant leaks

[Scott Palmer]

I searched the bug database and though ProgressBar leaks have been reported
before, they are supposed to be fixed in 8u40.  I'm seeing tons of leaks in
8u40.

Comparing heap dumps with jvisualvm I see in three minutes that my app has
accumulated 11,000 WeakReference and BindingHelperObserver objects that
appear to be associated with the ProgressBarSkin.

The chain to the GC root looks like this:

WeakReference
BindingHelperObserver
InvalidationListener[]
ExpressionHelper$Generic
ProgressBarSkin$1
ProgressBarSkin
ProgressBar

My application needs to run for a long time.  (Streaming realtime video -
i.e. a TV station broadcast for hours if not weeks at a time...)

I suspect this may be a regression in 8u40.  I will try to get that
confirmed.

Scott