Merge "Split out NetworkPriorityClassifier and UnderlyingNetworkRecord" am: 42bf9da702 am: 1baad423a7 am: f86fbfb8ba am: 6c6bae3f8c

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1901030

Change-Id: I6787c30f831a42bd245edbcf513be23ed6787409