Added backend tests with closure local function in local class

compiler/testData/codegen/box/closures/localClassFunClosure.kt

@@ -0,0 +1,8 @@
+fun box(): String {
+    val o = "O"
+    fun ok() = o + "K"
+    class OK {
+        val ok = ok()
+    }
+    return OK().ok
+}