backend/tests: add objectExpression{1,2,3}

backend.native/tests/codegen/objectExpression/2.kt

@@ -0,0 +1,17 @@
+fun main(args: Array<String>) {
+    val a = "a"
+
+    val x = object {
+        override fun toString(): String {
+            return foo {
+                a
+            }
+        }
+
+        fun foo(lambda: () -> String) = lambda()
+    }
+
+    print(x)
+}
+
+fun print(x: Any) = println(x.toString())