Avoid requesting selectors in Objective-C interop stubs

Selector references aren't DCEed and thus can cause false positive
API usage report from AppStore online validation.
Generate selectors by compiler instead.

Interop/Runtime/src/native/kotlin/kotlinx/cinterop/ObjectiveCImpl.kt

@@ -125,6 +125,10 @@ annotation class InteropStubs()
 @Retention(AnnotationRetention.SOURCE)
 internal annotation class ObjCMethodImp(val selector: String, val encoding: String)
 
+@PublishedApi
+@TypedIntrinsic(IntrinsicType.OBJC_GET_SELECTOR)
+internal external fun objCGetSelector(selector: String): COpaquePointer
+
 @kotlin.native.internal.ExportForCppRuntime("Kotlin_Interop_getObjCClass")
 private fun getObjCClassByName(name: NativePtr): NativePtr {
     val result = objc_lookUpClass(name)

Interop/StubGenerator/src/main/kotlin/org/jetbrains/kotlin/native/interop/gen/ObjCStubs.kt

@@ -178,6 +178,7 @@ class ObjCMethodStub(private val stubGenerator: StubGenerator,
 
         val kniReceiverParameter = "kniR"
         val kniSuperClassParameter = "kniSC"
+        val kniSelectorParameter = "kniSEL"
 
         val voidPtr = PointerType(VoidType)
 
@@ -199,6 +200,9 @@ class ObjCMethodStub(private val stubGenerator: StubGenerator,
                 TypedKotlinValue(voidPtr,
                         "getReceiverOrSuper($kniReceiverParameter, $kniSuperClassParameter)"))
 
+        kotlinObjCBridgeParameters.add(KotlinParameter(kniSelectorParameter, KotlinTypes.cOpaquePointer))
+        nativeBridgeArguments.add(TypedKotlinValue(voidPtr, kniSelectorParameter))
+
         val kotlinParameterNames = method.getKotlinParameterNames()
 
         method.parameters.forEachIndexed { index, it ->
@@ -224,7 +228,6 @@ class ObjCMethodStub(private val stubGenerator: StubGenerator,
                 returnType,
                 nativeBridgeArguments
         ) { nativeValues ->
-            val selector = "@selector(${method.selector})"
             val messengerParameterTypes = mutableListOf<String>()
             messengerParameterTypes.add("void*")
             messengerParameterTypes.add("SEL")
@@ -239,7 +242,7 @@ class ObjCMethodStub(private val stubGenerator: StubGenerator,
 
             val messenger = "(($messengerType) ${nativeValues.first()})"
 
-            val messengerArguments = listOf(nativeValues[1]) + selector + nativeValues.drop(2)
+            val messengerArguments = nativeValues.drop(1)
 
             "$messenger(${messengerArguments.joinToString()})"
         }