Remove wxOSX implementation of wxSpinCtrl and use the generic one.

wxOSX doesn't provide a native spinner+text control so it used a generic
implementation of wxSpinCtrl but a different one to the version found in
src/generic/spinctlg.cpp.

Just use the real generic version instead, it doesn't make sense to have two
different versions of the same generic control.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72413 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

build/bakefiles/files.bkl

@@ -2259,7 +2259,6 @@ IMPORTANT: please read docs/tech/tn0016.txt before modifying this file!
     src/osx/scrolbar_osx.cpp
     src/osx/slider_osx.cpp
     src/osx/spinbutt_osx.cpp
-    src/osx/spinctrl_osx.cpp
     src/osx/srchctrl_osx.cpp
     src/osx/statbox_osx.cpp
     src/osx/statline_osx.cpp
@@ -2386,7 +2385,6 @@ IMPORTANT: please read docs/tech/tn0016.txt before modifying this file!
     wx/osx/scrolbar.h
     wx/osx/slider.h
     wx/osx/spinbutt.h
-    wx/osx/spinctrl.h
     wx/osx/srchctrl.h
     wx/osx/statbmp.h
     wx/osx/statbox.h