Merge "Put tether/untether calls into handler queue" am: 2576c457de am: 0ea3966a88 am: c54b165f05

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/1535794

Change-Id: I3f51724e8b1e3775cbe65fb8b603b4d1e307469c