Fix compile errors with recent mingw.

Constify arguments to copy constuctors. Without this gcc fail to compile if classes used inside containers.
Error message is rather cryptic: " error: 'constexpr std::pair<_T1, _T2>::pair(const std::pair<_T1, _T2>&) [with _T1 = const int; _T2 = cocos2d::experimental::AudioPlayer]' declared to take const reference, but implicit declaration would take non-const"
Merge pull request #9115 from vovkasm/win32-audioengine-mingw-fix

Fix compile errors with recent mingw.