[JS IR] Add API to js runtime to throw linkage errors

libraries/stdlib/js-ir/runtime/unlinked.kt

@@ -0,0 +1,12 @@
+/*
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package kotlin.js
+
+internal class LinkageError(message: String?) : Error(message)
+
+internal fun throwLinkageError(message: String?): Nothing {
+    throw LinkageError(message)
+}