RFR: 8150469: unpack200 fails to compare crc correctly.

[Kumar Srinivasan]

Hello John, Alex,

Please review fix for https://bugs.openjdk.java.net/browse/JDK-8150469

The previous fix keeps the storage in the unpacker object which is
reset, for a multi-segmented pack archive, thus the computed crc32 is lost.

Now the storage is moved into the gzip container, which persists, across
multiple segments, I  also added the length check as specified by RFC 1952,
as  implemented by JDK.

http://hg.openjdk.java.net/jdk9/dev/jdk/file/e4af8119eba4/src/java.base/share/classes/java/util/zip/GZIPInputStream.java#l222

The review is at:
http://cr.openjdk.java.net/~ksrini/8150469/webrev.00/


Thanks
Kumar