Migrate IPsec CTS out of tests/tests/net Bug: 170487836 Test: atest CtsIkeTestCases Change-Id: I08f069c2a11f3daa3f0332c631055a1e0be7ce7b Merged-In: I08f069c2a11f3daa3f0332c631055a1e0be7ce7b (cherry picked from commit 51c0fa972e885d7b83bcbcce45770b57dfeac192)