Previously it was only pushing the module context for the call to
capture the module execution context. This is incorrect, as the capture
occurs upon function construction. This resulted in it capturing the
execution context that execute_module was called from, instead of the
newly created module_context.
f87041bf3a/Libraries/LibJS/Runtime/ECMAScriptFunctionObject.cpp (L92)
This can be demonstrated with the following setup:
index.html:
```html
<script>
var foo = 1;
</script>
<script type="module">
import {test} from "./scriptA.mjs";
</script>
```
scriptA.mjs:
```js
function foo() {
return {a: "b"};
}
export let test = await foo();
```
Before this fix, this would throw:
```
[TypeError] 1 is not a function (evaluated from 'foo')
at module code with top-level await
at module code with top-level await
at <unknown>
at <unknown>
```
Fixes#2245.
Resulting in a massive rename across almost everywhere! Alongside the
namespace change, we now have the following names:
* JS::NonnullGCPtr -> GC::Ref
* JS::GCPtr -> GC::Ptr
* JS::HeapFunction -> GC::Function
* JS::CellImpl -> GC::Cell
* JS::Handle -> GC::Root
Now that the heap has no knowledge about a JavaScript realm and is
purely for managing the memory of the heap, it does not make sense
to name this function to say that it is a non-realm variant.