[build] Name mangling mismangles names when emitting ES6

[rictic]

When testing shop's 3.0 branch, looking at the esm-bundled and es6-bundled outputs, we've got a function like:

function foo(bar, baz) {
  for (let i = 0; i < zim; i++) {
    zoop(bar, baz);
  }
}

and after minification we end up with:

function foo(h, i) {
  for (let i = 0; i < z; i++) {
    zoop(h, i);
  }
}

The param names clashes with the loop index after renaming, so instead of an array we see a number.

[rictic]

I'm temporarily turning off name mangling while I get a tighter repro of this issue.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[stale]

This issue has been automatically closed after being marked stale. If you're still facing this problem with the above solution, please comment and we'll reopen!