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

[Baesken, Matthias]

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