network/api: bound max port, handle out-of-range failure in Utility::… (#3194)

This was found via proto fuzzing the server config.

Risk Level: Low
Testing: New utility_test.

Signed-off-by: Harvey Tuch <htuch@google.com>

Mirrored from https://github.com/envoyproxy/envoy @ a87d265d1c1819926f2b2e8e7e866244fd40f574

envoy/api/v2/core/address.proto

@@ -39,7 +39,7 @@ message SocketAddress {
   string address = 2 [(validate.rules).string.min_bytes = 1];
   oneof port_specifier {
     option (validate.required) = true;
-    uint32 port_value = 3;
+    uint32 port_value = 3 [(validate.rules).uint32.lte = 65535];
     // This is only valid if :ref:`resolver_name
     // <envoy_api_field_core.SocketAddress.resolver_name>` is specified below and the
     // named resolver is capable of named port resolution.