Kotlin: Add test case for non serializable inner class query

Author: tamasvajk

java/ql/test/kotlin/query-tests/NonSerializableInnerClass/NonSerializableInnerClass.expected

@@ -0,0 +1,2 @@
+| NonSerializableInnerClassTest.kt:4:3:5:3 | X | Serializable inner class of non-serializable class $@. Consider making the class static or implementing readObject() and writeObject(). | NonSerializableInnerClassTest.kt:3:1:6:1 | A | A |
+| NonSerializableInnerClassTest.kt:9:3:10:3 | X | Serializable inner class of non-serializable class $@. Consider making the class static or implementing readObject() and writeObject(). | NonSerializableInnerClassTest.kt:8:1:11:1 | B | B |

java/ql/test/kotlin/query-tests/NonSerializableInnerClass/NonSerializableInnerClass.qlref

@@ -0,0 +1 @@
+Likely Bugs/Serialization/NonSerializableInnerClass.ql

java/ql/test/kotlin/query-tests/NonSerializableInnerClass/NonSerializableInnerClassTest.kt

@@ -0,0 +1,11 @@
+import java.io.Serializable
+
+class A {
+  class X : Serializable {
+  }
+}
+
+class B {
+  inner class X : Serializable {
+  }
+}