[automerger skipped] DO NOT MERGE Cherry-pick: ICU-20536 Japanese era Reiwa support in ICU4J 56 am: 18c03b9631 -s ours am skip reason: subject contains skip directive skipped: 384bda0e59 skipped: 635b03e6ab skipped: 61a767aaf7 skipped: f01bd6b25c skipped: 68a29eb164

Change-Id: Ie20866aa2d8b9b391c93e54136e144fcf5e748b3