Enhance sock_addr_local syscall (#1320)

Slightly change the __wasi_sock_addr_local interface - since we already have
a `__wasi_addr_t` structure which is an union, there's no need for passing the
length around - the address buffer will always have the right length (i.e. max
of all address families).

core/shared/platform/windows/win_socket.c

@@ -171,5 +171,14 @@ os_socket_addr_resolve(const char *host, const char *service,
 {
     errno = ENOSYS;
 
+    return BHT_ERROR;
+}
+
+int
+os_socket_addr_local(bh_socket_t socket, uint8_t *buf, size_t buflen,
+                     uint16_t *port, uint8_t *is_ipv4)
+{
+    errno = ENOSYS;
+
     return BHT_ERROR;
 }