RFR: [8u] 8219890: Calendar.getDisplayName() returns empty string for new Japanese Era on some locales

[Andrew John Hughes]

Webrev: https://cr.openjdk.java.net/~andrew/openjdk8/8219890/webrev.01/
Bug: https://bugs.openjdk.java.net/browse/JDK-8219890

This is largely a clean patch, with two minor adjustments besides path
changes:

* The copyright change in
src/share/classes/java/util/JapaneseImperialCalendar.java is not
applied, as it already has 2019.
* The changes to names in
test/java/util/Calendar/JapaneseEraNameTest.java had to be manually
applied due to one being commented out in 8u (JDK-8220020)
-- 
Andrew :)

Senior Free Java Software Engineer
Red Hat, Inc. (http://www.redhat.com)

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