traverse.clearCache is not a function

**Describe the bug**

I know there are other issues already posted for same question, but those still do not contain any actual answers.

**To Reproduce**
Go to Babeljs.io, and click "Minify".
Minimal code to reproduce the bug
Even no code shows the error "traverse.clearCache is not a function". Writing any simple code such as let b = 5; will simply just state the same error and no output.

This happens on latest version of Chrome from Windows 10, and Chrome from MacOS Mojave. Have not tested on linux, but I don't think its platform dependent issue at this point.
```js
```

**Actual Output**
If there is no Error thrown,

```js
"traverse.clearCache is not a function"

```

**Expected Output**
No error message, and the output should be produced.

```js
```

Reproduce the error by opening Babeljs.io, selecting Minify, and submitting empty input or `let b = 5;`. Trace where the browser reports `traverse.clearCache is not a function` in the minify entry point and verify that the page produces minified output without the error.

Written by the indexing model from the issue text.