Adds tests for PreferenceDataStore funcionality.

Test: cts-tradefed run cts-dev -m CtsPreference2TestCases -t
android.preference2.cts.PreferenceDataStoreTest

Also fixes: b/33094864

Change-Id: Ib207a7254b2cac0dbf606dcc793ee9e0f60f7df0
3 files changed