RFR : 8196854 :TestFlushableGZIPOutputStream failing with IndexOutOfBoundsException

A jdk8u (and earlier) issue where some new/recent test code meant that IndexOutOfBoundsException could be thrown. https://bugs.openjdk.java.net/browse/JDK-8196854 http://cr.openjdk.java.net/~coffeys/webrev.8196854/webrev/ The buf array was never required and I've verified that the original 8189789 issue can still be reproduced with a buggy JDK. -- Regards, Sean.