Fix(?) try/catch

[NotHyper-474]

Related issue: FunkinCrew/Funkin#3031

Test code:

var a:String = null;
try {
  trace(a.length);
}
catch (err:Dynamic) {
  trace("Catched error: " + err);
}

Output:
hscriptClass(assets/test.hxc):20: Catched error: hscriptClass(assets/test.hxc):14: Invalid access to field length

[NotHyper-474]

For some reason here it's Interp but for me it would always be _Interp. I hope this doesn't mean it changes somehow.

[NotHyper-474]

This currently throws an error in the program itself, although we might want to use errorEx here instead? Or whatever way Polymod uses to handle errors.