test: remove third argument from assert.strictEqual()

In file test/parallel/test-stream-transform-final.js the ten calls to
assert.strictEqual() use a string literal as third argument. When
a AssertionError occurs, it reports the string literal and not the
first two arguments, so the third agrument is removed and made a
comment just above the call to assert.strictEqual().

PR-URL: https://github.com/nodejs/node/pull/22051


Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Anatoli Papirovski <apapirovski@mac.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Jon Moss <me@jonathanmoss.me>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>