C#: Update test expected output.

Author: michaelnebel

csharp/ql/test/library-tests/properties/Properties19.expected

@@ -4,6 +4,7 @@
 | properties.cs:62:13:62:13 | access to property Y | properties.cs:58:37:58:39 | set_Y |
 | properties.cs:82:46:82:51 | access to property X | properties.cs:70:32:70:34 | get_X |
 | properties.cs:83:39:83:44 | access to property Y | properties.cs:74:13:74:15 | set_Y |
+| properties.cs:160:13:160:20 | access to property Value | properties.cs:142:13:142:15 | set_Value |
 | properties.cs:161:25:161:32 | access to property Value | properties.cs:150:13:150:15 | get_Value |
 | properties.cs:164:13:164:20 | access to property Value | properties.cs:142:13:142:15 | set_Value |
 | properties.cs:165:25:165:32 | access to property Value | properties.cs:141:13:141:15 | get_Value |