Get CtsProviderTestCases targeting modern SDK.

Grant tests the "write_settings" appop they needs to run, and test
against well-known key.

Move away from FileCopyHelper, which uses deprecated
MODE_WORLD_READABLE mode.  Define TestSRSProvider to get a valid
provider to notify against.

Bug: 120429729, 120577010
Test: atest CtsProviderTestCases
Change-Id: I5b78ee2df66562f1356aa36c3c92781c5aca5d43