Pass all offload-exempt prefixes into OffloadController

Additionally:
    - eliminate useless TetherMasterUtilState

Test: as follows
    - built
    - flashed
    - booted
    - runtest frameworks passes
Bug: 29337859
Bug: 32163131

Merged-In: I6adcdbd6a4f14bd2cdaa056cfc0cf9c573a165b9
Merged-In: I5e689bcf5dd048ee9f9bd0c32b16d7c2e4c0268d
Merged-In: Ifd3817bd4569682d77a70f8192432391a573f6d8
Merged-In: I1ea57fbe322e26246f1d8b459519f18be1297467
Change-Id: I0482ac9dd9e8ba558b253643dbc01875ce9475ef
(cherry picked from commit be8ee08f)