ipn/ipnlocal: delete redundant TestStatusWithoutPeers

We have tstest/integration nowadays.

And this test was one of the lone holdouts using the to-be-nuked
SetControlClientGetterForTesting.

Updates #11649

Change-Id: Icf8a6a2e9b8ae1ac534754afa898c00dc0b7623b
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

tstest/integration/integration_test.go

@@ -382,6 +382,11 @@ func TestTwoNodes(t *testing.T) {
 		if peer.ID == st.Self.ID {
 			return errors.New("peer is self")
 		}
+
+		if len(st.TailscaleIPs) == 0 {
+			return errors.New("no Tailscale IPs")
+		}
+
 		return nil
 	}); err != nil {
 		t.Error(err)