[RFR] 8204539: improve error messages in matchJavaTZ [windows]

Hi, could you please review this small change that improves the error messages in matchJavaTZ . A reason of the failure is added to the message , and also the offset where the error happened . Bug : https://bugs.openjdk.java.net/browse/JDK-8204539 Webrev : http://cr.openjdk.java.net/~mbaesken/webrevs/8204539/ Thanks, Matthias