Kotlin: add test for incorrect declaration stack

Author: tamasvajk

java/ql/test/kotlin/library-tests/declaration-stack/Test.kt

@@ -0,0 +1,5 @@
+abstract class Base(func:() -> Unit = {}) { }
+
+class Derived : Base({
+    data class Dc(val foo: String)
+})

java/ql/test/kotlin/library-tests/declaration-stack/test.expected

@@ -0,0 +1 @@
+| Test.kt:3:1:5:2 | IrInstanceInitializerCall outside constructor |

java/ql/test/kotlin/library-tests/declaration-stack/test.ql

@@ -0,0 +1,5 @@
+import java
+import semmle.code.java.Diagnostics
+
+from Diagnostic d
+select d