RFR (JAXP) 8059327 : XML parser returns corrupt attribute value

[huizhe wang]

Hi,

This is a regression caused by changeset: 
http://cr.openjdk.java.net/~joehw/jdk9/8027359/webrev/. The fix then is 
to recover those changes that modified the buffer. Please review.

http://cr.openjdk.java.net/~joehw/jdk9/8059327/webrev/
https://bugs.openjdk.java.net/browse/JDK-8059327

Thanks,
Joe