@babel/preset-env: `DEBUG` option

Using targets:
{
  "chrome": "71"
}

Using modules transform: auto

Using plugins:
  proposal-numeric-separator { "chrome":"71" }
  proposal-logical-assignment-operators { "chrome":"71" }
  proposal-nullish-coalescing-operator { "chrome":"71" }
  proposal-optional-chaining { "chrome":"71" }
  syntax-json-strings { "chrome":"71" }
  syntax-optional-catch-binding { "chrome":"71" }
  syntax-async-generators { "chrome":"71" }
  syntax-object-rest-spread { "chrome":"71" }
  proposal-export-namespace-from { "chrome":"71" }
  transform-modules-commonjs { "chrome":"71" }
  proposal-dynamic-import { "chrome":"71" }

Using polyfills with `usage` option:

[<CWD>/packages/babel-preset-env/test/fixtures/debug/usage-corejs2-proposals-chrome-71-1/input.js] Added following core-js polyfill:
  web.dom.iterable { "chrome":"71" }
