[12] RFR: 8212941: Loosen the range of JapaneseEra

[naoto . sato]

Hello,

Please review the fix to the following issue:
https://bugs.openjdk.java.net/browse/JDK-8212941

The proposed fix and CSR (not approved yet) are located at:

http://cr.openjdk.java.net/~naoto/8212941/webrev.02/
https://bugs.openjdk.java.net/browse/JDK-8212942

This change is intended to loosen the spec of JapaneseEra so that later 
era additions won't require unnecessary spec changes. This is 
particularly important for the maintenance releases.

Naoto