Fix and test usb function configuration change

Allow stop TETHERING_NCM no matter ncm is used for TETHERING_USB or
TETHERING_NCM.

Add a test:
1. NCM is started for TETHERING_NCM
2. The config changes to use NCM for TETHERING_USB.
3. Then the config changes to use RNDIS for TETHERING_USB.

Also let some logs not only print in dumpsys, but also in logcat to
easiler debug unit test.

Bug: 185649441
Test: atest TetheringTests
Original-Change: https://android-review.googlesource.com/1740778
Merged-In: Ia8d76a29646f36941cbb16cd68ae6887100ec8ec
Change-Id: Ia8d76a29646f36941cbb16cd68ae6887100ec8ec
2 files changed