NodeJsSetupTask: Check for the node executable instead of its directory

We want NodeJs to be downloaded again if nodeBinDir exists but the node
binary is missing.

Fixes https://youtrack.jetbrains.com/issue/KT-34989.

libraries/tools/kotlin-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/targets/js/nodejs/NodeJsSetupTask.kt

@@ -24,7 +24,7 @@ open class NodeJsSetupTask : DefaultTask() {
     init {
         @Suppress("LeakingThis")
         onlyIf {
-            settings.download && !env.nodeBinDir.isDirectory
+            settings.download && !File(env.nodeExecutable).isFile
         }
     }