Add thread ID reuse to API contract

This make explicit that thread IDs should not be reused to point to new
threads as this may cause issues in applications that expect threads to
remain consistent.

Test: Tested by CTS test in CtsTelephonyProviderTestCases
Bug: 122616805
Change-Id: I068943c402084c524f7e7002044a7efc59ef796d
1 file changed