[K/JS] Fix nameBindings for ES-modules after the ES-modules external declarations optimization

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/transformers/irToJs/JsNameLinkingNamer.kt

@@ -90,6 +90,7 @@ class JsNameLinkingNamer(
                 else -> JsImport.Target.Default(nameRef)
             }
             imports[this] = JsImport(jsModule, importSubject)
+            nameMap[this] = name
         } else {
             importedModules += JsImportedModule(jsModule, name, nameRef)
         }

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/utils/serialization/JsIrAstSerializer.kt

@@ -97,7 +97,7 @@ private class JsIrAstSerializer {
     }
 
     fun append(fragment: JsIrProgramFragment): JsIrAstSerializer {
-        importedNames += fragment.imports.map { fragment.nameBindings[it.key]!! }
+        importedNames += fragment.imports.map { fragment.nameBindings[it.key] ?: error("No binding for tag ${it.key}") }
         fragmentSerializer.writeFragment(fragment)
         return this
     }