exec: Add vectorized support for IN

[jseldess]

PR: cockroachdb/cockroach#38546

From release notes:

Added vectorized support for the IN selection operator. [#38546][#38546] {% comment %}doc{% endcomment %}

[ericharmeling]

From the user's perspective, IN and NOT IN are already supported operators, so it looks like we don't need documentation support for this particular item, unless there is a behavior change that I'm missing. Please reopen if you disagree!

Also, all vectorized execution documentation should be addressed in #4790.