Revert "Revert "Add getUiccSlots() and switchSlots() in TelephonyManager.""

This reverts commit 4e044e66.

Reason for revert: The original failure was not caused by this CL and this CL does not depend on the broken one.

Test: on phone

Change-Id: Id5b5ca33e5836b6ccb1d38ab7ee5166a95955fbb