Printing of both union and tuple types was broken such that the first
type was always skipped due to a bug.

Bug: v8:8015
Change-Id: I4bd215a9d8fa5bc7e017dd28e66512f4961228d1
Reviewed-on: https://chromium-review.googlesource.com/1199365Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55569}