backend/tests: Add tests for local function closures

backend.native/tests/codegen/function/localFunction.kt

@@ -0,0 +1,11 @@
+fun main(args : Array<String>) {
+    val x = 1
+    fun local0() = println(x)
+    fun local1() {
+        fun local2() {
+            local1()
+        }
+        local0()
+    }
+    println("OK")
+}