Merge "Make FileUtils#createDir threadsafe" am: 5232082243 am: bc1b11029b

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1623101

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Id70ab2f8c4a73d74e6b0e63353e66521bd6c3581