That way we don't need to internalize kValue property names on object literals
(both STRING and identifier tokens). This speeds up object literal preparsing
by quite a bit (15% on a microbenchmark; 7-8% on actual object literals looking
like json from FB).

Change-Id: I9d7baeb94f1a8e4f7e3b7cd6406a826ba37017f3
Reviewed-on: https://chromium-review.googlesource.com/c/1491605Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#59915}