RFR (JDK 12/java.base) 8213325: (props) Properties.loadFromXML does not fully comply with the spec

[Joe Wang]

Hi,

Please review a patch to bring the small footprint parser for 
java.util.Properties compliant with the specification.

JBS: https://bugs.openjdk.java.net/browse/JDK-8213325
webrevs: http://cr.openjdk.java.net/~joehw/jdk12/8213325/webrev/

Thanks,
Joe