Remove try/catch from JS __instanceof.
Remove try/catch from JS __instanceof.

I had to tweak the patch a bit to get the unit tests to pass. Closes
issue 1685.

pleclech/hacking-haxe,pleclech/hacking-haxe,pleclech/hacking-haxe,pleclech/hacking-haxe,pleclech/hacking-haxe,pleclech/hacking-haxe