X87: [es6] Spread in array literals

X87: [es6] Spread in array literals

port 9502e91adbed48a546463aa848656d07619d14e6 (r28534)

original commit message:

    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=

Review URL: https://codereview.chromium.org/1152173002

Cr-Commit-Position: refs/heads/master@{#28606}