Replace 3 @CorePlatformApi usages into single API validateTzData() am: dcbbd24626 am: 50a6cc1061 am: 2fbef589f7 am: f345c15166

Original change: https://android-review.googlesource.com/c/platform/system/timezone/+/1494437

Change-Id: Ib618e61234373022b9d8af70d4492971a37c898e