refactor TestListenerConnectDeadlines to avoid data races (#3201)

Fixes #3179

privval/socket_test.go

@@ -98,16 +98,17 @@ func TestListenerAcceptDeadlines(t *testing.T) {
 
 func TestListenerConnectDeadlines(t *testing.T) {
 	for _, tc := range listenerTestCases(t, time.Second, time.Millisecond) {
-		readyc := make(chan struct{})
-		donec := make(chan struct{})
-		go func(ln net.Listener) {
-			defer close(donec)
+		go func(dialer Dialer) {
+			_, err := dialer()
+			if err != nil {
+				panic(err)
+			}
+		}(tc.dialer)
 
-			c, err := ln.Accept()
+		c, err := tc.listener.Accept()
 		if err != nil {
 			t.Fatal(err)
 		}
-			<-readyc
 
 		time.Sleep(2 * time.Millisecond)
 
@@ -121,13 +122,5 @@ func TestListenerConnectDeadlines(t *testing.T) {
 		if have, want := opErr.Op, "read"; have != want {
 			t.Errorf("for %s listener, have %v, want %v", tc.description, have, want)
 		}
-		}(tc.listener)
-
-		_, err := tc.dialer()
-		if err != nil {
-			t.Fatal(err)
-		}
-		close(readyc)
-		<-donec
 	}
 }