WifiManager#pingSupplicant is deprecated and its semantics had changed.
So remove it in testWifiManagerActions to fix the test.
Bug: 37991667
Test: cts-tradefed run cts-dev --module CtsNetTestCases --test
android.net.wifi.cts.WifiManagerTest#testWifiManagerActions
Change-Id: I9b64cb6d03c253f143a78caca72b75678973034b