This patch moves some test setup functions to util classes in preparation for IKEv2 VPN tests which will use those same utilities. Bug: 148582947 Test: atest IpSecManagerTunnelTest; passing Change-Id: I9aeafa45ab515ce72a72c3de6f70fb26e32e7fd4 Merged-In: I9aeafa45ab515ce72a72c3de6f70fb26e32e7fd4 (cherry picked from commit 30432fa7640603c1e746b7d8c83e2e6052d8f967)