[JS IR] Generate stub for exported functions with default params

see https://youtrack.jetbrains.com/issue/KT-43407

js/js.translator/testData/box/jsExport/dataClass.kt

@@ -1,4 +1,5 @@
 // MODULE_KIND: COMMON_JS
+// SKIP_DCE_DRIVEN
 // SKIP_MINIFICATION
 
 // FILE: api.kt
@@ -14,17 +15,40 @@ data class AltPoint(val x: Int, val y: Int)
 
 // FILE: main.kt
 external interface JsResult {
-    val res: String
+    val copy00: String
+    val copy01: String
+    val copy10: String
+    val copy11: String
+    val component1: Int
+    val component2: Int
 }
 
 @JsModule("lib")
 external fun jsBox(): JsResult
 
 fun box(): String {
-    val res = jsBox().res
-    if (res != "[13::11]") {
-        return "Fail1: ${res}"
+    val res = jsBox()
+    if (res.copy00 != "[3::7]") {
+        return "Fail1: ${res.copy00}"
     }
+    if (res.copy01 != "[3::11]") {
+        return "Fail2: ${res.copy01}"
+    }
+    if (res.copy10 != "[15::7]") {
+        return "Fail3: ${res.copy10}"
+    }
+    if (res.copy11 != "[13::11]") {
+        return "Fail4: ${res.copy11}"
+    }
+    if (res.component1 != 3) {
+        return "Fail5: ${res.component1}"
+    }
+    if (res.component2 != 7) {
+        return "Fail6: ${res.component2}"
+    }
+
+
+
 
     return "OK"
 }