deps: upgrade npm to 3.6.0

This is the big one! After this I anticipate getting back into a weekly cadence of upstreaming things to Node.js.

Contains the changes in these releases:

• https://github.com/npm/npm/releases/tag/v3.4.0
• https://github.com/npm/npm/releases/tag/v3.4.1
• https://github.com/npm/npm/releases/tag/v3.5.0
• https://github.com/npm/npm/releases/tag/v3.5.1
• https://github.com/npm/npm/releases/tag/v3.5.2
• https://github.com/npm/npm/releases/tag/v3.5.3
• https://github.com/npm/npm/releases/tag/v3.5.4
• https://github.com/npm/npm/releases/tag/v3.6.0

Notable inclusions are:

• The clarified split between Terms of Service and the CLI's own license (see the discussion in https://github.com/npm/npm/releases/tag/v3.5.1 and #3959 (closed) for more context).
• Several important changes to how edge cases involving bundleDependencies are handled.
• Tests don't implode when running under a node prerelease.
• You also only get one warning now about using a prerelease version rather than dozens and dozens from failed engine checks.
• A handful of minor new user affordances in 3.6.0– in particular npm outdated reports linked modules & npm version can now take from-git as an argument.

r: @Fishrock123 r: @jasnell r: @mikeal