Fix most UDP issues on Mac OS

runtime/bin/socket_patch.dart

Index: runtime/bin/socket_patch.dart
diff --git a/runtime/bin/socket_patch.dart b/runtime/bin/socket_patch.dart
index 423761497e2c8e1dac11f66a15d784713a13af2a..52ff3d9273d10fa74369738a7034b1d1aba2786b 100644
--- a/runtime/bin/socket_patch.dart
+++ b/runtime/bin/socket_patch.dart
@@ -773,7 +773,7 @@ class _NativeSocket extends NativeFieldWrapperClass1 {
     if (Platform.isMacOS && addr.type == InternetAddressType.IP_V4) {
       if (interface != null) {
         for (int i = 0; i < interface.addresses.length; i++) {
-          if (addr.type == InternetAddressType.IP_V4) {
+          if (interface.addresses[i].type == InternetAddressType.IP_V4) {
             return interface.addresses[i];
           }
         }
@@ -782,7 +782,7 @@ class _NativeSocket extends NativeFieldWrapperClass1 {
             "The network interface does not have an address "
             "of the same family as the multicast address");
       } else {
-        // Default to the ANY address if on iterface is specified.
+        // Default to the ANY address if no iterface is specified.
         return InternetAddress.ANY_IP_V4;
       }
     } else {