[8u] RFR: 8162572: Update License Header for all JAXP sources

[Alex Kashchenko]

Hi,

Please review a backport of JDK-8162572:

Bug (not public): https://bugs.openjdk.java.net/browse/JDK-8162572

Original commit: https://hg.openjdk.java.net/jdk10/jdk10/jaxp/rev/2fdbfbde3bc0

8u webrev: https://cr.openjdk.java.net/~akasko/jdk8u/8162572/webrev.00/

This change can make it easier to backport subsequent JAXP parity
issues to 8u. There are no code changes, only copyright headers are
changed. Majority of the files apply cleanly, the following files were
resolved manually:

src/com/sun/org/apache/xalan/internal/lib/Extensions.java
src/com/sun/org/apache/xalan/internal/xsltc/dom/SimpleResultTreeImpl.java
src/com/sun/org/apache/xerces/internal/impl/XML11NSDocumentScannerImpl.java
src/com/sun/org/apache/xml/internal/dtm/DTMConfigurationException.java
src/com/sun/org/apache/xml/internal/dtm/DTMException.java
src/com/sun/org/apache/xml/internal/dtm/DTMManager.java
src/com/sun/org/apache/xml/internal/serializer/SerializerFactory.java
src/com/sun/org/apache/xml/internal/serializer/dom3/DOM3SerializerImpl.java
src/com/sun/org/apache/xml/internal/serializer/dom3/DOMConstants.java
src/com/sun/org/apache/xml/internal/serializer/dom3/DOMErrorHandlerImpl.java
src/com/sun/org/apache/xml/internal/serializer/dom3/DOMErrorImpl.java
src/com/sun/org/apache/xml/internal/serializer/dom3/DOMLocatorImpl.java
src/com/sun/org/apache/xml/internal/serializer/dom3/DOMOutputImpl.java
src/com/sun/org/apache/xml/internal/serializer/dom3/DOMStringListImpl.java
src/com/sun/org/apache/xml/internal/serializer/dom3/LSSerializerImpl.java
src/com/sun/org/apache/xml/internal/serializer/dom3/NamespaceSupport.java
src/com/sun/org/apache/xml/internal/serializer/utils/AttList.java
src/com/sun/org/apache/xml/internal/serializer/utils/DOM2Helper.java
src/com/sun/org/apache/xml/internal/utils/DOMOrder.java
src/com/sun/org/apache/xpath/internal/XPath.java
src/com/sun/org/apache/xpath/internal/axes/FilterExprWalker.java
src/com/sun/org/apache/xpath/internal/axes/WalkerFactory.java

-- 
-Alex