[Tests] Migrate backend-independent tests from native to compiler/testData.

^KT-65979

compiler/testData/codegen/box/function/defaults2.kt

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2010-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
+ * that can be found in the LICENSE file.
+ */
+// WITH_STDLIB
+
+import kotlin.test.*
+
+
+fun Int.foo(inc0:Int, inc:Int = 0) = this + inc0 + inc
+
+fun box(): String {
+    val v = 42.foo(0)
+    if (v != 42) {
+        println("test failed v:$v expected:42")
+        throw Error()
+    }
+    return "OK"
+}