test: refactor test-module-loading assertions

When there are three arguments in strictEqual() call and
AssertionError exists, the previous two values are not printed.
This improves debugging messages visibility
when there is a fail.
The messages were removed where the instruction
is self-explanatory.

PR-URL: https://github.com/nodejs/node/pull/21833


Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Trivikram Kamat <trivikr.dev@gmail.com>