R=titzer@chromium.org
TEST=unittests/FunctionBodyDecoderTest
BUG=v8:8091

Change-Id: Iad8d0dbc193c8e2f1f6359632fb2dbad28c154e2
Reviewed-on: https://chromium-review.googlesource.com/1195368Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55488}