It is hard to know where ifError is actually triggered due to the
original error being thrown.
This changes it by wrapping the original error in a AssertionError.
This has the positive effect of also making clear that it is indeed
a assertion function that triggered that error.
The original stack can still be accessed by checking the `actual`
property.
PR-URL: https://github.com/nodejs/node/pull/18247
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>