[cpp] overload resolution for TNew

[vonagam]

Adds overloading support for new in cpp.

[vonagam]

Rebased on #9516 and added a test.

[Simn]

On a related note, I think we should try adding a tclass_field to TNew so the generators don't have to play this resolution game.

However, my bigger concern is super() calls because that would require a different AST node altogether.

[vonagam]

Oh, right forgot about super. Thanks.

[vonagam]

Ah, misinterpreted what you said in super concern as about untested effect of this PR on super resolution in cpp.
Checked if it wasn't working - it works. Added inheritance with super calls to the test just in case.

Yeah, i find it strange that haxe resolves overloads and then a generator has to do it again.

[vonagam]

Simply rebased (now that #9516 was merged), nothing new.

@hughsando can this be given the green light?

[hughsando]

thanks - looks good