!0 -> true and !1 -> false etc in the parser.
This clashes with some of the typing logic in asm.js,
and can show up in some real programs in the wild (at least in past asm.js
versions).

BUG= https://bugs.chromium.org/p/v8/issues/detail?id=4203
R=aseemgarg@chromium.org,jpp@chromium.org

Review-Url: https://codereview.chromium.org/2372823004
Cr-Commit-Position: refs/heads/master@{#39798}