RFR: 8189789: tomcat gzip-compressed response bodies appear to be broken in update 151

[Seán Coffey]

Looking to fix a recent regression that appeared in 8u151. Thanks goes 
to Sherman for the src patch. Paul Hohensee has also helped by provided 
some test code. I've been able to modify an existing test to mimic the 
behaviour seen with FlushableGZIPOutputStream which is found in Tomcat 7.x.

Sherman is working on a patch for JDK 10. For unix OSes, JDK 10 operates 
with the zlib version found on the OS.

bug : https://bugs.openjdk.java.net/browse/JDK-8189789
webrev : http://cr.openjdk.java.net/~coffeys/webrev.8189789.jdk8u/webrev/

regards,
Sean.