Adds SDK-target specific networking tests. Adds a test verifying that apps targeting <= SDK 29 have access to the MAC address of ethernet interfaces. Adds SELinux tests for apps targeting SDK 29. Bug: 141455849 Change-Id: I9b9ba084dd1c58d01b97f807d7e0122f059c5121 Fix: 149544376 Test: atest CtsSelinuxTargetSdk27TestCases Test: atest CtsSelinuxTargetSdk28TestCases Test: atest CtsSelinuxTargetSdk29TestCases Test: atest CtsSelinuxTargetSdkCurrentTestCases