tree 0f45aa3e7cf20113697641ae1d56eea93a148535
parent d64e93bc3ff6c72aedcd6846e3c26c009831dc7d
author Victor Chang <vichang@google.com> 1562187876 -0700
committer Victor Chang <vichang@google.com> 1574699556 +0000

Cherry-pick: ICU-20689 Fix race condition in UMutex code, leading to random crashes.

Fix that UMutex::getMutex returns nullptr due to race-condition.

Bug: 144403455
Test: m droid and device boots
Change-Id: I42e4bf2e4a67b9f48fb6ed9cf265876d373b52ea