WARN if system-property is already set and is being overridden

WARN if system-property is already set and is being overridden

If user sets a system property using the java opts or on the command line and the same system property is defined in the standalone.xml, then the standalone.xml value overrides that passed on the commandline/JAVA_OPTS, a warning would be useful as looking at the logs (and ps), it shows value1 passed on the command line and nothing indicating that the value was changed later.

JAVA_OPTS="$JAVA_OPTS -Dmy.system.property=value1"

    <system-properties>
        <property name="my.system.property" value="value2"/> 
   </system-properties>