Compiler warns undefined for some global classes in `[#if <var> instanceof <class>}`

https://svelte.dev/repl/11d3f7dc166f412eae208b1e9be81418?version=3
```svelte
<script>
	export let foo;
</script>

{#if foo instanceof Node}
	_
{/if}
```
```
'Node' is not defined (5:20)
```