Allow the decoding of multiple tables, and allow these tables to have
any reference type. In addition, rename function-tables (in different
occurrences) to tables.

R=titzer@chromium.org

Bug: v8:7581
Change-Id: I191ea8e303b76563f9d91ae7447b373c4760d8b8
Reviewed-on: https://chromium-review.googlesource.com/1019581
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#54355}