Fix leakage in adoptCalendar

Issue discovered in https://chromium-review.googlesource.com/c/v8/v8/+/1771954

Bug: chromium:997401
Change-Id: I1afa6beb195b5d350f7d4c4e39ad7a0b20a8b99a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/deps/icu/+/1776986
Reviewed-by: Jungshik Shin <jshin@chromium.org>
3 files changed