Add testRegisterTetheringEventCallback for CtsTetheringTest

Bug: 150632712
Bug: 150631563
Test: atest CtsTetheringTest

Change-Id: I55895c8b26acb7ec905d75d1f4b2a8964b13187a
1 file changed
tree: cabe7c26e8fe62421f8ff032f5b67e48d0f27a11
  1. tests/