Previously, all control points would get replaced, which led to
performance issues that was worked around in this PR. By comparing
control points, we're able to get good performance without requiring the
workaround.
This was added with the intention of tracking the offset when already at
the start (the most common case when you're using the tap timing
wizard), but was also seeking when the user may be much further beyond
or before it.
Addresses https://github.com/ppy/osu/discussions/18741#discussioncomment-2975051.