[cpp] Fix unreflective iterators causing Null Function error

[tobil4sk]

Unreflective iterators were broken in 0b2b0da, because the iterator fields are now accessed via dynamic field lookup instead of direct calls (which is also less optimal in general). This partially reverts 4a181fd, which fixes #12369.

Presumably, the original commit was intended to fix: #11891 (comment), so this probably requires testing (and ideally a proper test case) to prevent that issue from returning. @yuxiaomao would you be able to check if this causes that has no field hasNext() error to return?

[yuxiaomao]

I do not have the original repro, but (probably) the same project build with your branche + development, I have the following errors. (no error on other tested projects)

[ERROR] (unknown position)

     | Type not found : ArrayIterator

[ERROR] src/ui/win/Debrief.hx:485: characters 15-31

 485 |     for (c in debrief.captured) {
     |               ^^^^^^^^^^^^^^^^
     | hxbit.ArrayProxyIterator<hxbit.ObjProxy_Op_ent_Player_u_st_Unit> should be hxbit.ArrayProxyIterator_hxbit_ObjProxy_Op_ent_Player_u_st_Unit