fix MSRV in windows specific tests

Author: hanna-kruppe

tests/socket.rs

@@ -446,9 +446,9 @@ where
             socket.as_raw_socket() as _,
             WinSock::SIO_GET_MULTIPLE_EXTENSION_FUNCTION_POINTER,
             (&guid as *const GUID) as *const _,
-            size_of_val(&guid) as u32,
+            mem::size_of_val(&guid) as u32,
             table.as_mut_ptr() as *mut _,
-            size_of_val(&table) as u32,
+            mem::size_of_val(&table) as u32,
             (&mut bytes as *mut i32) as *mut _,
             ptr::null_mut(),
             None,