Add test for IpConfiguration and also address review comments from aosp/1171795. Bug: 139268426 Test: CtsNetTestCasesLatestSdk:android.net.cts.IpConfigurationTest Change-Id: Ib30a98e11bdcd9d473b713f7e4c317172b14f000 Merged-In: Ib30a98e11bdcd9d473b713f7e4c317172b14f000 (cherry picked from commit 8e208eb353263bddca4d93a7a67a5f978316b0cc)