RFR JDK9 (JAXP) 8152527: Relative rewriteSystem with xml:base at group level failed

[huizhe wang]

Hi,

Please review a fix to rewrite* matching issue.  When the rewrite* 
entries are in a group entry, the current match with entries in a group 
entry needs to be recorded just as when they are outside of a group.

JBS: https://bugs.openjdk.java.net/browse/JDK-8152527
webrevs: http://cr.openjdk.java.net/~joehw/jdk9/8152527/webrev/

Thanks,
Joe