tests: Update external tests (1.1.2-dev-393)

backend.native/tests/external/codegen/box/extensionFunctions/kt3298.kt

@@ -0,0 +1,13 @@
+var result = ""
+fun result(r: String) { result = r }
+
+object Foo {
+    private operator fun String.unaryPlus() = "(" + this + ")"
+
+    fun foo() = { result(+"Stuff") }()
+}
+
+fun box(): String {
+    Foo.foo()
+    return if (result == "(Stuff)") "OK" else "Fail $result"
+}