C#: Add test exposing missing phi flow

Author: hvitved

csharp/ql/test/library-tests/dataflow/delegates/DelegateFlow.cs

@@ -124,4 +124,13 @@ public unsafe void M18()
         delegate*<Action<int>, void> fnptr = &M2;
         fnptr((i) => { });
     }
+
+    void M19(Action a, bool b)
+    {
+        if (b)
+            a = () => {};
+        a();
+    }
+
+    void M20(bool b) => M19(() => {}, b);
 }

csharp/ql/test/library-tests/dataflow/delegates/DelegateFlow.expected

@@ -24,3 +24,4 @@ delegateCall
 | DelegateFlow.cs:89:35:89:37 | delegate call | DelegateFlow.cs:65:10:65:12 | M11 | DelegateFlow.cs:91:13:91:47 | delegate creation of type MyDelegate |
 | DelegateFlow.cs:89:35:89:37 | delegate call | DelegateFlow.cs:74:17:74:19 | M12 | DelegateFlow.cs:92:13:92:15 | delegate creation of type MyDelegate |
 | DelegateFlow.cs:89:35:89:37 | delegate call | DelegateFlow.cs:93:13:93:21 | (...) => ... | DelegateFlow.cs:93:13:93:21 | (...) => ... |
+| DelegateFlow.cs:132:9:132:11 | delegate call | DelegateFlow.cs:131:17:131:24 | (...) => ... | file://:0:0:0:0 | <empty> |