C#: Some test examples of collection like types that should be excluded.

csharp/ql/test/utils/model-generator/Summaries.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Linq;
+using System.Collections;
 using System.Collections.Generic;
 
 namespace Summaries;
@@ -85,6 +86,31 @@ public class CollectionFlow
     {
         return new List<string> { tainted };
     }
+
+    public string[] ReturnComplexTypeArray(string[] a)
+    {
+        return a;
+    }
+
+    public List<byte> ReturnBulkTypeList(List<byte> a)
+    {
+        return a;
+    }
+
+    public Dictionary<int, string> ReturnComplexTypeDictionary(Dictionary<int, string> a)
+    {
+        return a;
+    }
+
+    public Array ReturnUntypedArray(Array a)
+    {
+        return a;
+    }
+
+    public IList ReturnUntypedList(IList a)
+    {
+        return a;
+    }
 }
 
 public class IEnumerableFlow