C#: Add dataflow test for partial constructors.

Author: michaelnebel

csharp/ql/test/library-tests/dataflow/constructors/ConstructorFlow.expected

@@ -274,6 +274,7 @@ subpaths
 | Constructors.cs:143:25:143:26 | access to local variable o1 : Object | Constructors.cs:137:29:137:32 | Obj1 : Object | Constructors.cs:137:19:137:20 | this [Return] : R1 [property Obj1] : Object | Constructors.cs:143:18:143:31 | object creation of type R1 : R1 [property Obj1] : Object |
 | Constructors.cs:143:29:143:30 | access to local variable o2 : Object | Constructors.cs:137:42:137:45 | Obj2 : Object | Constructors.cs:137:19:137:20 | this [Return] : R1 [property Obj2] : Object | Constructors.cs:143:18:143:31 | object creation of type R1 : R1 [property Obj2] : Object |
 testFailures
+| Constructors.cs:164:29:164:48 | // ... | Missing result: hasValueFlow=11 |
 #select
 | Constructors.cs:15:18:15:19 | access to field s1 | Constructors.cs:5:29:5:45 | call to method Source<Object> : Object | Constructors.cs:15:18:15:19 | access to field s1 | $@ | Constructors.cs:5:29:5:45 | call to method Source<Object> : Object | call to method Source<Object> : Object |
 | Constructors.cs:33:18:33:19 | access to field s1 | Constructors.cs:21:29:21:45 | call to method Source<Object> : Object | Constructors.cs:33:18:33:19 | access to field s1 | $@ | Constructors.cs:21:29:21:45 | call to method Source<Object> : Object | call to method Source<Object> : Object |

csharp/ql/test/library-tests/dataflow/constructors/Constructors.cs

@@ -145,6 +145,25 @@ public void M7()
         Sink(r1.Obj2); // $ hasValueFlow=10
     }
 
+    public partial class CPartial
+    {
+        public object Obj { get; }
+
+        public partial CPartial(object o);
+    }
+
+    public partial class CPartial
+    {
+        public partial CPartial(object o) => Obj = o;
+    }
+
+    public void M8()
+    {
+        var o = Source<object>(11);
+        var cPartial = new CPartial(o);
+        Sink(cPartial.Obj); // $ hasValueFlow=11
+    }
+
     public static void Sink(object o) { }
 
     public static T Source<T>(object source) => throw null;