title: correct import of core-js when using useBuiltins entry and browserslist
body: <p>My webpack.config is adding <code>core-js/stable</code> and <code>regenerator-runtime/runtime</code> to the webpack config entry property:</p>
  <pre><code>const config = {
      name: 'client',
      target: 'web',
      entry: ['core-js/stable', 'regenerator-runtime/runtime', 'src/index'],
  </code></pre>
  <p>My babel config is using <code>useBuiltIns: 'entry'</code></p>
  <p>and I have the following <code>.browserslistrc</code></p>
  <pre><code>&gt;0.25%, not dead
  </code></pre>
  <p>My bundle size still looks pretty huge, I have highlighted the core-js bits in the webpack analyzer image below</p>
  <p><a href="https://i.stack.imgur.com/HDBHC.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/HDBHC.jpg" alt="enter image description here" /></a></p>
  <p>Does babel use the <code>browserslistrc</code> when <code>useBuiltins</code> is set to <code>entry</code> and is there anyway I can tell that only the relevant bits of core-js are imported?</p>