Add CtsNetTestCases to TEST_MAPPING am: ad380c1de6

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/1612014

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: I35c8e85d9c321a96703e879ff2ce230749d7f9dd
tree: d69b934050fda4bc254faa8f9a2596a118d49e3a
  1. tests/
  2. Tethering/
  3. .gitignore
  4. OWNERS
  5. PREUPLOAD.cfg
  6. TEST_MAPPING