[11u] RFR: 8249867: xml declaration is not followed by a newline

[Doerr, Martin]

Hi,

JDK-8249867 is backported to 11.0.11-oracle. I'd like to backport it for parity.
It applies almost cleanly and resolution is trivial.

Manual resolution steps:
PrettyPrintTest.java:
- Update copyright year.
- Add bug id to the @bug line.

ToStream.java:
- Update copyright year.
- Update time stamp in @LastModified line.

LSSerializerImpl.java:
- Skip Copyright year and time stamp update because the Copyright header is missing in 11u.

Bug:
https://bugs.openjdk.java.net/browse/JDK-8249867

Original change:
https://git.openjdk.java.net/jdk/commit/69ee314b

11u backport:
http://cr.openjdk.java.net/~mdoerr/8249867_xml_11u/webrev.00/

Please review.

Best regards,
Martin