DO NOT MERGE Apply upstream changes of TestUnicodeExtension [U]

Recent CLDR changes cause tests to fail. I've cherry-picked
changes to fix test_shortTZID test case only from [1].

Bug: 323820851
Test: see system/timezone

[1] https://github.com/openjdk/jdk/commit/3684b4b5f24b413408b1b6d206917931b855844e
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:7b9790174a05fd1d9bf528bc1633b39a5d41db07)
Merged-In: I228d5991c685a35989f7c0fccb6647afb938520e
Change-Id: I228d5991c685a35989f7c0fccb6647afb938520e
1 file changed