[11] RFR: 8202088: Japanese new era implementation

Hi, Please review the changes to the subject issue: https://bugs.openjdk.java.net/browse/JDK-8202088 The proposed change is located at: http://cr.openjdk.java.net/~naoto/8202088/webrev.01/ This is the implementation part of the upcoming Japanese new era, starting from May 1st, 2019. Current anticipation is that the new name won't be known till one month prior to the beginning of the era. So it's not possible to make changes to the JDK with the proper name. Instead, here we are going to implement the new era with a place holder name which will be immediately replaced with the proper name once it's known. The CSR is currently under review: https://bugs.openjdk.java.net/browse/JDK-8202336 Naoto