[macosx] 8u60 JScrollPane scroll bar bouncing when using trackpad inertial scroll

Mac OS X only: In an 8u60 (or higher) Swing app using a wide JScrollPane, the scroll bar shakes and bounces when repeatedly scrolling up or down with a track pad using inertial scrolling (two fingers).

Problem does not occur on JDK 8 updates older than 8u60 (8u40, 8u45, and 8u51 were tested and do not show problem).

Problem occurs only with inertial scrolling with trackpad, and does not occur when using USB mouse.