Remove compatibility layer for util.getSystemErrorName()

[ehmicky]

Although the Node.js documentation says that util.getSystemErrorName() is added in 9.7.0, it's actually been back-ported 6 months later to 8.12.0. I tried it with nvm and confirm this function works in 8.12.0.

We use a compatibility layer for this function, which can now be removed.

I am a little unclear whether we support 8.0.0 to 8.11.0, or only the later 8.*.* versions:

• the package.json engines.node field shows >=8, which is translated by npm to >=8.0.0 (using semver under the hood).
• but the version tested on Travis is 8, which is translated to the latest 8.16.0 (using nvm under the hood).

(I think those two should be in sync, but that's a separate issue).

As a side effect, this would also fix test coverage there.

[sindresorhus]

I am a little unclear whether we support 8.0.0 to 8.11.0, or only the later 8.. versions:

Generally, it's expected that users upgrade patch versions as those contain important security fixes. We can continue this in sindresorhus/meta#8.

[sindresorhus]

Yay. Feels good getting that removed.