test: remove unused deprecation code

Currently there are two tests that specify a third argument, a
deprecation code string, when calling common.expectWarning. The
function only takes two arguments and this third argument is not used.

This commit removes the deprecation code.

PR-URL: https://github.com/nodejs/node/pull/19317


Reviewed-By: Yuta Hiroto <hello@hiroppy.me>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Khaidi Chu <i@2333.moe>
Reviewed-By: Jackson Tian <shyvo1987@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>