[JS IR BE] Do not create $default stub for external function and any its fake override

js/js.translator/testData/box/jsModule/externalClassWithDefaults.js

@@ -0,0 +1,13 @@
+define("lib", [], function() {
+    function A(ss) {
+        this.s = ss || "A"
+    }
+    A.prototype.foo = function (y) {
+        return y || "K";
+    };
+    A.prototype.bar = function (y) {
+        return y || "O";
+    };
+
+    return A;
+});

js/js.translator/testData/box/jsModule/externalClassWithDefaults.kt

@@ -0,0 +1,44 @@
+// EXPECTED_REACHABLE_NODES: 1284
+// MODULE_KIND: AMD
+package foo
+
+@JsModule("lib")
+external open class A(ss: String = definedExternally) {
+    val s: String
+    fun foo(y: String = definedExternally): String = definedExternally
+    fun bar(y: String = definedExternally): String = definedExternally
+}
+
+class C: A {
+    constructor(ss: String) : super(ss) {}
+    constructor() : super() {}
+
+    fun qux(s: String = "O") = s
+}
+
+
+fun box(): String {
+    val a = A()
+    val c = C()
+
+    val r1 = a.foo("O") + c.foo()
+    if (r1 != "OK") return "Fail1: $r1"
+
+    val r2 = a.bar() + c.bar("K")
+    if (r2 != "OK") return "Fail2: $r2"
+
+    val r3 = c.qux() + c.qux("K")
+    if (r3 != "OK") return "Fail3: $r3"
+
+    if (a.s != "A") return "Fail4: ${a.s}"
+    if (c.s != "A") return "Fail5: ${c.s}"
+
+    val a2 = A("A2")
+    val c2 = C("C2")
+
+    val r6 = a2.s + c2.s
+    if (r6 != "A2C2") return "Fail6: $r6"
+
+    return "OK"
+
+}