Add back autogeneration rules

Will be removed in https://github.com/ppy/osu/pull/6604

osu.Game/Beatmaps/ControlPoints/ControlPointGroup.cs

@@ -30,10 +30,19 @@ namespace osu.Game.Beatmaps.ControlPoints
 
         public void Add(ControlPoint point)
         {
-            point.AttachGroup(this);
+            var existing = controlPoints.FirstOrDefault(p => p.GetType() == point.GetType());
+
+            if (existing != null)
+            {
+                // autogenerated points should not replace non-autogenerated.
+                // this allows for incorrectly ordered timing points to still be correctly handled.
+                if (point.AutoGenerated && !existing.AutoGenerated)
+                    return;
 
-            foreach (var existing in controlPoints.Where(p => p.GetType() == point.GetType()).ToArray())
                 Remove(existing);
+            }
+
+            point.AttachGroup(this);
 
             controlPoints.Add(point);
             ItemAdded?.Invoke(point);

osu.Game/Beatmaps/ControlPoints/ControlPointInfo.cs

@@ -184,9 +184,6 @@ namespace osu.Game.Beatmaps.ControlPoints
 
         public void Add(double time, ControlPoint newPoint, bool force = false)
         {
-            if (!force && SimilarPointAt(time, newPoint)?.EquivalentTo(newPoint) == true)
-                return;
-
             GroupAt(time, true).Add(newPoint);
         }
 

osu.Game/Beatmaps/Formats/LegacyBeatmapDecoder.cs

@@ -374,14 +374,12 @@ namespace osu.Game.Beatmaps.Formats
 
                 beatmap.ControlPointInfo.Add(time, controlPoint);
             }
-            else
+
+            beatmap.ControlPointInfo.Add(time, new DifficultyControlPoint
             {
-                beatmap.ControlPointInfo.Add(time, new DifficultyControlPoint
+                SpeedMultiplier = speedMultiplier,
-                {
+                AutoGenerated = timingChange
-                    SpeedMultiplier = speedMultiplier,
+            });
-                    AutoGenerated = false
-                });
-            }
 
             beatmap.ControlPointInfo.Add(time, new EffectControlPoint
             {