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

^KT-65979

compiler/testData/codegen/box/delegatedProperty/observable.kt

@@ -0,0 +1,32 @@
+/*
+ * 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.
+ */
+// JVM_ABI_K1_K2_DIFF: KT-63864
+// WITH_STDLIB
+
+import kotlin.test.*
+
+import kotlin.properties.Delegates
+
+val sb = StringBuilder()
+
+class User {
+    var name: String by Delegates.observable("<no name>") {
+        prop, old, new ->
+        sb.appendLine("$old -> $new")
+    }
+}
+
+fun box(): String {
+    val user = User()
+    user.name = "first"
+    user.name = "second"
+
+    assertEquals("""
+        <no name> -> first
+        first -> second
+
+    """.trimIndent(), sb.toString())
+    return "OK"
+}