Const propagation for inlined dynamic argument ignores haxe.extern.AsVar

```haxe
function main() {
var x:haxe.extern.AsVar = 10;
#if php
php.Syntax.code("{0} = 0", x);
#elseif js
js.Syntax.code("{0} = 0", x);
#end
Sys.print(x);
}
```
This issue happens across targets:
```
haxe --main Main --php testphp -D analyzer-optimize
haxe --main Main --js out.js -lib hxnodejs -D analyzer-optimize
```

PHP output:
```php
$b = 10;
$b = 0;
echo("10");
```

JS output:
```js
var b = 10;
b = 0;
process.stdout.write("10");
```

This does not happen if you use trace or another function instead of print or println.

The real life scenario where I ran into this was: https://github.com/HaxeFoundation/haxe/pull/12520#issuecomment-3821542487.

Start by running the two Haxe commands in the issue with analyzer optimization enabled, using the sample involving haxe.extern.AsVar, php.Syntax.code or js.Syntax.code, and Sys.print. Compare the generated PHP and JavaScript with the shown output; done means the assignment through the dynamic argument is reflected when Sys.print emits the value, rather than the original constant.

Written by the indexing model from the issue text.