[13] RFR: 8222980: Upgrade IANA Language Subtag Registry to Version 2019-04-03

[naoto.sato at oracle.com]

Hello,

Please review the changes to the following issue:

https://bugs.openjdk.java.net/browse/JDK-8222980

The proposed changeset is located at:

http://cr.openjdk.java.net/~naoto/8222980/webrev.00/

It is simply replacing the subtag registry file with the most up-to-date 
one, along with test case changes.

Naoto