LibJS: Cleanup unwind state when transferring control out of a finalizer

This does two things:
* Clear exceptions when transferring control out of a finalizer
  Otherwise they would resurface at the end of the next finalizer
  (see test the new test case), or at the end of a function
* Pop one scheduled jump when transferring control out of a finalizer
  This removes one old FIXME

Userland/Libraries/LibJS/Bytecode/Interpreter.h

@@ -69,6 +69,7 @@ public:
     void leave_unwind_context();
     void catch_exception(Operand dst);
     void restore_scheduled_jump();
+    void leave_finally();
 
     void enter_object_environment(Object&);