Square character support for the Japanese new era

Summary

Support for the square character for the Japanese new era

Problem

A new code point (U+32FF) will be assigned for the upcoming Japanese new era [1]. Currently the code point is unassigned, thus various static methods in java.lang.Character class returns values for an invalid code point.

[1] http://blog.unicode.org/2018/09/new-japanese-era.html

Solution

Modify the character properties for that particular code point so that it would be regarded as a Japanese square era name, similar to the one that represents Meizi (U+337E). Specifically,

Character.isDefined(0x32FF) returns 'true'.
Character.getType(0x32FF) returns Character.OTHER_SYMBOL
Character.getName(0x32FF) returns "SQUARE ERA NAME NEWERA"
Character.getDirectionality(0x32FF) returns Character.DIRECTIONALITY_LEFT_TO_RIGHT
Character.UnicodeScript(0x32FF) returns Character.UnicodeScript.COMMON

This change will not include any composition/decomposition changes. It will be included in the upcoming ICU4J changes in their version 63.

Specification

This is a behavioral change, so no spec change is anticipated.