browserlist Firefox >= 52 adds regeneratorRuntime also if async is supported

## Bug Report

With browserlist `Firefox >= 52` and using async functions, babel adds regeneratorRuntime also if this version of firefox supports [async functions](https://caniuse.com/async-functions).

Adding `Firefox >= 53` fixes this issue.

**Current behavior**

Babel polyfills async functions with regeneratorRuntime and the browser gives error if you don't include regeneratorRuntime: `Uncaught ReferenceError: regeneratorRuntime is not defined`

**Input Code**

In .browserslistrc

```
Firefox >= 52
```

In js:

```
const accessEvent = async () => {
}
accessEvent()
```

**Expected behavior**

Babel should not polyfill with this browserlist.

**Babel Configuration (babel.config.js, .babelrc, package.json#babel, cli command, .eslintrc)**

- Filename: `babel.config.js`

```js
module.exports = {
presets: [
[
'@babel/preset-env',
{
useBuiltIns: 'entry',
corejs: 3,
},
],
],
}
```

**Environment**

```
System:
OS: macOS 11.2.2
Binaries:
Node: 14.15.5 - /usr/local/bin/node
Yarn: 1.3.2 - /usr/local/bin/yarn
npm: 6.14.11 - /usr/local/bin/npm
npmPackages:
@babel/core: ^7.13.10 => 7.13.10
@babel/preset-env: ^7.13.10 => 7.13.10
babel-loader: ^8.2.2 => 8.2.2
webpack: 5.26.1 => 5.26.1
```
- Babel version(s): 7.13.10
- Node/npm version: v14.15.5
- How you are using Babel: webpack

Reproduce the case using .browserslistrc with Firefox >= 52, babel.config.js, and the async-function input. Trace how @babel/preset-env resolves this browser target and decides whether to transform async functions; done means the generated output no longer requires regeneratorRuntime for supported Firefox versions.

Written by the indexing model from the issue text.