RFR [14/java.xml] 7148925: StAXSource causes exceptions to be thrown with certain wellformed XML instances

[Joe Wang]

Please review a fix for an Exception caused by StAXSource. The fix adds 
code that processes the prolog and misc content as specified by the XML 
specification, and removes the code that made incorrect assumption about 
XML document structure.

https://bugs.openjdk.java.net/browse/JDK-7148925
http://cr.openjdk.java.net/~joehw/jdk14/7148925/webrev/

Thanks,
Joe