Move kernelToTag to NetworkStatsFactory. am: adab7b1cc3 am: 4f3022fa09

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1964913

Change-Id: I3bd1b8fb38cb302612139b8ba1940e72e0dc2380
tree: ce313f7e52a300f03d8d9bfb45fd55fc63a2ce4e
  1. framework/
  2. framework-t/
  3. service-t/
  4. services/
  5. tests/