We should pass false as has_braces argument to create FunctionLiteral
for top level function.

R=dgozman@chromium.org,bmeurer@chromium.org
TBR=bmeurer@chromium.org

Bug: none
Change-Id: I397f31b562d32c71f3a12bfc9ceeed16c367aa80
Reviewed-on: https://chromium-review.googlesource.com/1098018
Commit-Queue: Aleksey Kozyatinskiy <kozyatinskiy@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Reviewed-by: Yang Guo <yangguo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53769}