[JS IR BE] Add isTopLevel property to IrFunction

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

@@ -10,6 +10,7 @@ import org.jetbrains.kotlin.ir.backend.js.utils.JsGenerationContext
 import org.jetbrains.kotlin.ir.backend.js.utils.Namer
 import org.jetbrains.kotlin.ir.declarations.IrClass
 import org.jetbrains.kotlin.ir.declarations.IrFunction
+import org.jetbrains.kotlin.ir.declarations.IrPackageFragment
 import org.jetbrains.kotlin.ir.expressions.*
 import org.jetbrains.kotlin.js.backend.ast.*
 
@@ -83,6 +84,9 @@ fun translateCallArguments(expression: IrMemberAccessExpression, context: JsGene
 val IrFunction.isStatic: Boolean
     get() = parent is IrClass && dispatchReceiverParameter == null
 
+val IrFunction.isTopLevel: Boolean
+    get() = parent is IrPackageFragment
+
 fun JsStatement.asBlock() = this as? JsBlock ?: JsBlock(this)
 
 fun JsName.objectInstanceName() = "${ident}_instance"