Create a new user once before all the tests are run.

Bug: 190663736
Bug: 190664705
Bug: 190666890
Bug: 190664071
Test: atest ./hostsidetests/blobstore/src/com/android/cts/host/blob/BlobStoreMultiUserTest.java
Change-Id: I303964bd229c7c36d6c955acf308eaa131f4862f
2 files changed