ObjCExport: deprecate exporting data class componentN methods to Obj-C

The Objective-C methods for Kotlin data class componentN methods
shouldn't have been generated in the first place -- the corresponding
Kotlin methods are required to make the destructuring work in Kotlin,
and don't help in Objective-C or Swift.

Calling them manually from Objective-C or Swift doesn't make much sense.
So now we deprecate this, in order to remove these methods from
Objective-C header completely later.

^KT-42641
^KT-49516 Fixed

kotlin-native/backend.native/tests/objcexport/dataClassComponentMethods.swift

@@ -0,0 +1,34 @@
+/*
+ * Copyright 2010-2022 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.
+ */
+
+import Kt
+
+private func testComponentMethodsAreStillAccessible() throws {
+    let d = DataClassWithComponentMethods(x: 1, y: 2)
+    try assertEquals(actual: d.component1(), expected: 1)
+    try assertEquals(actual: d.component2(), expected: 2)
+}
+
+// Absence of deprecation attributes is checked by comparing "lazy header".
+private func testRegularComponentMethodsAreAccessible() throws {
+    let r = RegularClassWithComponentMethods()
+    try assertEquals(actual: r.component1(), expected: 3)
+    try assertEquals(actual: r.component3(), expected: 4)
+}
+
+private func testTopLevelComponentMethodsAreAccessible() throws {
+    try assertEquals(actual: DataClassComponentMethodsKt.component1(), expected: 5)
+    try assertEquals(actual: DataClassComponentMethodsKt.component4(), expected: 6)
+}
+
+class DataClassComponentMethodsTests : SimpleTestProvider {
+    override init() {
+        super.init()
+
+        test("testComponentMethodsAreStillAccessible", testComponentMethodsAreStillAccessible)
+        test("testRegularComponentMethodsAreAccessible", testRegularComponentMethodsAreAccessible)
+        test("testTopLevelComponentMethodsAreAccessible", testTopLevelComponentMethodsAreAccessible)
+    }
+}