Request for review and approval: 8162598: XSLTC transformer swallows empty namespace declaration which is needed to undeclare default namespace

[Langer, Christoph]

Hi,

can you please approve the backport of this fix:
Bug: https://bugs.openjdk.java.net/browse/JDK-8162598
JDK9 Change: http://hg.openjdk.java.net/jdk9/dev/jaxp/rev/e66cdc2de6b0
Discussion thread: http://mail.openjdk.java.net/pipermail/core-libs-dev/2016-July/042635.html

The actual changes and the test have to be split between jdk and jaxp repos:
JAXP change: http://cr.openjdk.java.net/~clanger/webrevs/8162598_jaxp.8udev/
Test change in jdk repo: http://cr.openjdk.java.net/~clanger/webrevs/8162598_jdk.8udev/

Unfortunately, the patch does not apply after unshuffling. I also had to transport some of the cleanups that were made in other changes to resolve. But now everything builds and tests run cleanly. The test had to be extracted into an own test as the test structure differs between jdk9 and 8.

@Joe: Please review the jdk8 changes in order to get approval.

Thanks & Best regards
Christoph