[Bug] when `ThisExpression` marked as `Purish`, deadcode plugin will remove arrowy function plugin build result

Bug Report

@babel/types @7.12.5: This pr marked ThisExpression as Purish, it will cause babel-plugin-minify-dead-code-elimination removes @babel/plugin-transform-arrow-functions compiled result. For example:

<div onClick={() => {
  this.a = 1;
} }></div>

It will be transformed by @babel/plugin-transform-arrow-functions:

var _this = this
<div onClick={function() {
  _this.a = 1;
} }></div>

After this pr, it will be transformed as:

<div onClick={function() {
  this.a = 1;
} }></div>

So, the this will be undefined.

[xqin]

Please revoke this version!!!

[nicolo-ribaudo]

I’ll release once CI on main finishes