npm / arborist / #790

push

fix: hidden lockfiles were not respected on Node v10.0-10.12

* Polyfill withFileTypes option for fs.readdir

This was causing hidden lockfiles to be silently ignored in
node versions that did not support fs.readdir with this option.

* @npmcli/installed-package-contents@1.0.7
* other polyfills to make tests pass on node v10.1
* tell node not to spam warnings during tests
* Suppress warnings and fix up snapshots for v10.1
* more aggressive snapshot cleanup for node pretty printing
* ci: do not check linting on node versions that don't support it
* ensure single source of truth for 'test' script

2802 of 2802 branches covered (100.0%)

Branch coverage included in aggregate %.

3814 of 3814 relevant lines covered (100.0%)

566.27 hits per line