minify makes shl operation (<<) bigger

Hi

thanks for babel-minify! I use it for a js1k compo and discovered that the code

```js
array.fill(0xff<<24 | (time%16 ? 0 : 0x38));
```

is minified to

```js
g.fill(-16777216|(n%16?0:56))
```

I use minify without any additional parameter, only `node_modules/babel-minify/bin/minify.js index.js`

#### Expected Output (updated)

```js
g.fill(0xff<<24|(n%16?0:56))
```

Start with the command shown in the issue, node_modules/babel-minify/bin/minify.js, and reproduce the transformation using the provided JavaScript snippet. Trace the minification path that changes 0xff<<24 into -16777216, then verify the result against the expected output and confirm the generated code is no longer larger.

Written by the indexing model from the issue text.