C#: Add a primary constructor QL library test.

Author: michaelnebel

csharp/ql/test/library-tests/constructors/PrimaryConstructor.expected

@@ -0,0 +1,2 @@
+| constructors.cs:23:18:23:19 | C1 |
+| constructors.cs:28:18:28:19 | C2 |

csharp/ql/test/library-tests/constructors/PrimaryConstructor.ql

@@ -0,0 +1,8 @@
+/**
+ * @name Test for primary constructors
+ */
+
+import csharp
+
+from PrimaryConstructor c
+select c

csharp/ql/test/library-tests/constructors/PrintAst.expected

@@ -17,3 +17,30 @@ constructors.cs:
 #   16|             -1: [TypeMention] int
 #   16|             0: [LocalVariableAccess] access to local variable i
 #   16|             1: [IntLiteral] 0
+#   21| [NamespaceDeclaration] namespace ... { ... }
+#   23|   1: [Class] C1
+#   23|     4: [InstanceConstructor,PrimaryConstructor] C1
+#-----|       2: (Parameters)
+#   23|         0: [Parameter] o
+#   23|           -1: [TypeMention] object
+#   23|         1: [Parameter] s
+#   23|           -1: [TypeMention] string
+#   25|     5: [InstanceConstructor] C1
+#-----|       2: (Parameters)
+#   25|         0: [Parameter] o
+#   25|           -1: [TypeMention] object
+#   25|       3: [ConstructorInitializer] call to constructor C1
+#   25|         0: [ParameterAccess] access to parameter o
+#   25|         1: [StringLiteralUtf16] "default"
+#   25|       4: [BlockStmt] {...}
+#   28|   2: [Class] C2
+#-----|     3: (Base types)
+#   28|       0: [TypeMention] C1
+#   28|     4: [InstanceConstructor,PrimaryConstructor] C2
+#-----|       2: (Parameters)
+#   28|         0: [Parameter] o
+#   28|           -1: [TypeMention] object
+#   28|         1: [Parameter] s
+#   28|           -1: [TypeMention] string
+#   28|         2: [Parameter] i
+#   28|           -1: [TypeMention] int

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

@@ -17,3 +17,13 @@ static Class()
         }
     }
 }
+
+namespace PrimaryConstructors
+{
+    public class C1(object o, string s)
+    {
+        public C1(object o) : this(o, "default") { }
+    }
+
+    public class C2(object o, string s, int i) : C1(o, s) { }
+}