RFR: 8225217: Backout: JDK-8224814: Remove dead JNIHandleBlock freelist code

[David Holmes]

Bug: https://bugs.openjdk.java.net/browse/JDK-8225217
webrev: http://cr.openjdk.java.net/~dholmes/8225217/webrev/

Original patch: http://hg.openjdk.java.net/jdk/jdk/rev/47d928ba8733

It turns out the freelist code wasn't quite dead but played a role in 
cleaning up deleted local references, without which we end up with 
"null" handles being left around.

Simplest solution is to backout that change and it will be re-examined 
for 14.

Thanks,
David
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