[v8.x] deps: update npm to 5.4.2

This includes three npm releases, one of which is pretty big (5.4.0).

Changes of Note

• Significant performance boost for installations from cache (~10%+)
• A number of bugfixes for important and severe bugs affecting installation on all supported platforms, but particularly noticeable on Windows.
• More Windows-related fixes for npx.
• #17844 Make package-lock.json sorting locale-agnostic. This will cause some users to see seemingly spurious diffs on their pkglocks if they were using previous versions of npm5, because, for example, JSONStream is sorted into a different location. This is fine and will go away as people upgrade.

Changelogs

• v5.4.0
• v5.4.1
• v5.4.2

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines

Affected core subsystem(s)