Add tests for java.net APIs am: 51368dbed4 am: f08cc77a20

Original change: https://googleplex-android-review.googlesource.com/c/platform/libcore/+/18234479

Change-Id: I1afd6e353674498d3fc8492776a0c968068b1a39
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>