Changes

Fix Bug 621, JVM Crashes During X11 Shutdown while closing all unclosed display connections.

This is a regression of JOGL commit f2cfb6119a3663715ed2d572643949b3bef58662 to fix Bug 610.

Commit f2cfb6119a3663715ed2d572643949b3bef58662 closed all open display connections at
JVM shutdown in order of their creation.
This is required IF the driver is the proprietary ATI on X11.
X11Util.setMarkAllDisplaysUnclosable(true) is called in this case.

However, this behavior causes a SIGSEGV for other GPU driver, i.e. Nvidia :)

This fix only closes the pending display connections in their respective order
IF X11Util.getMarkAllDisplaysUnclosable() == true.
Hence the 'new' cleanup as introduced in the offending commit
is only performed on the erroneous ATI driver.

Manually tested w/ TestGearsES2AWT, see it's commandline options for details.