JDK 9 RFR of JDK-8075692: jaxp/test/Makefile references (has been removed) win32 directory in jtreg

[Amy Lu]

File structure has changed in the new jtreg distribution (4.1/b11), 
there are no platform specific bin directories any more.
This fix is for updating jaxp/test/Makefile accordingly.
bug: https://bugs.openjdk.java.net/browse/JDK-8075692
webrev: http://cr.openjdk.java.net/~amlu/8075692/webrev.00/

I also need a sponsor for this fix.

Thanks,
Amy