Bug Report

Current Behavior
If we spread an array with hole ([1,, 2] of new Array(3), for example), the code generated from Babel don't convert the holes to undefined.

Input Code
Using babel, this code

[1, ...[2,, 3]]

generates this:

[1].concat([2,, 3]) // returns [1, 4, (empty), 3]

Expected behavior/code

[1, ...[2,, 3]] // should returns [1, 2, undefined, 3]

Babel Configuration (.babelrc, package.json, cli command)

{
  plugins: ["@babel/plugin-transform-spread"]
}

Environment

• Babel version(s): lasted version from git
• Node/npm version: Node v9, NPM 5.6.0
• OS: macOS High Sierra
• Monorepo: yep
• How you are using Babel: CLI

Additional context/Screenshots
I found this bug when I'm doing this PR for fix a similar bug: #8872
This PR isn't fix this another bug.