Detect CI properly in flatOptions generation

* Also, test this with a mock, so that tests pass in CI.
* test: streamline snapshot on config test
* test: add workaround for node 10's broken promises
* test: make cache dir cross-platform consistent in config test

PR-URL: #1719
Credit: @isaacs
Close: #1719
Reviewed-by: @ruyadorno

lib/utils/config.js

@@ -9,6 +9,8 @@ const {
   }
 } = require('@npmcli/config')
 
+const ciDetect = require('@npmcli/ci-detect')
+
 const isWindows = require('./is-windows.js')
 
 const editor = process.env.EDITOR ||
@@ -132,7 +134,7 @@ const defaults = {
   'prefer-online': false,
   preid: '',
   production: process.env.NODE_ENV === 'production',
-  progress: !process.env.TRAVIS && !process.env.CI,
+  progress: !ciDetect(),
   proxy: null,
   'https-proxy': null,
   noproxy: null,