WifiManagerTest: Use addNetwork + enableNetwork instead of save

WifiManager.save() is an asynchronous operation. This is sometime
causing the tests to be flaky (dropShellIdentity occurs while this is
being processed). Use the synchronous legacy API's instead for rewinding
the effects of factory reset.

Bug: 152048238
Test: atest android.net.wifi.cts.WifiManagerTest
Change-Id: Ibb0e04cf931511fcda1b1a81fd6eda4583196c2e
1 file changed