[es6] Spread in array literals

[es6] Spread in array literals

This allows you to put iterables into your array literals
and the will get spread into the array.

  let x = [0, ...range(1, 3)];  // [0, 1, 2]

This is done by treating the array literal up to the first
spread element as usual, including using a boiler plate
array, and then appending the remaining expressions and rest
expressions.

BUG=v8:3018
LOG=N

Review URL: https://codereview.chromium.org/1125183008

Cr-Commit-Position: refs/heads/master@{#28534}