[objects] Fix type of ByteCodeArray::source_position_table

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}

src/builtins/base.tq

@@ -359,6 +359,7 @@ type Null extends Oddball;
 type Undefined extends Oddball;
 type True extends Oddball;
 type False extends Oddball;
+type Exception extends Oddball;
 type EmptyString extends String;
 type Boolean = True|False;
 

src/objects/code.tq

@@ -8,7 +8,7 @@ extern class BytecodeArray extends FixedArrayBase {
   // TODO(v8:8983): bytecode array object sizes vary based on their contents.
   constant_pool: FixedArray;
   handler_table: ByteArray;
-  source_position_table: Undefined|ByteArray;
+  source_position_table: Undefined|ByteArray|Exception;
   frame_size: int32;
   parameter_size: int32;
   incoming_new_target_or_generator_register: int32;