[m91] Fix crash caused by locale assign/move operators

https://unicode-org.atlassian.net/browse/ICU-21587
https://bugs.chromium.org/p/chromium/issues/detail?id=1194899

Bug: chromium:1194899
Change-Id: I39edcf04f43c52f6937365e50f521fab3679568b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/deps/icu/+/2842864
Reviewed-by: Jungshik Shin <jshin@chromium.org>
(cherry picked from commit d25bdc013cb0d0d9b1b7c53beb1ab2a30323341c)
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/deps/icu/+/2845799
Reviewed-by: Frank Tang <ftang@chromium.org>