Bug 1028 - AMD Windows driver thread hinders JVM process to exit/end, caused by _not_ destroying the SharedResource context

SharedResourceRunner stop() method
is invoked by JMV shutdown hook and GLProfile/GLDrawableFactory.shutdown*().

It shall issue SharedResource.releaseSharedResource() for all implementations,
e.g. X11/GLX and Windows/WGL.

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Root cause is a GL driver thread keeping the process alive.

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On X11/GLX we destroy the shared context and the shared drawable.

On Windows/WGL we only destroy the shared drawable,
knowing that destroying the shared context caused a driver bug in the past.

Will enable the shared context destruction, which is the proper way.

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Commiting this patch to see whether our jenkins builds won't crash
due to previous experienced issues.