Declare that ByteCodeArray's source_position_table entry can also
contain Exception. (Also adds the Exception type to base.tq).

This is just a clean up for now but could be required if torque starts
generating checks for Union types (including differentiating between
different Oddballs).

Change-Id: Ie34ade100040df2f3a2e8120613b6b29d604984a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2019483
Auto-Submit: Dan Elphick <delphick@chromium.org>
Commit-Queue: Tobias Tebbi <tebbi@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66009}