Remove wxInitData::argvOrig which is not needed, finally

We never really used the "original" version of the command line, i.e.
before it was (possibly) modified by gtk_init_check(), so don't bother
keeping it and just free the pointers corresponding to the arguments
consumed by GTK in wxGTK code.

There should be no real changes, this is just a simplification.

include/wx/private/init.h

@@ -33,12 +33,6 @@ struct WXDLLIMPEXP_BASE wxInitData
     int argc = 0;
     wchar_t** argv = nullptr;
 
-    // We also need to keep their original copies as they can be modified
-    // during initialization (e.g. GTK removes GTK-specific parameters from
-    // it), but we must free the originally allocated array at the end.
-    int argcOrig = 0;
-    wchar_t** argvOrig = nullptr;
-
 #ifdef __WINDOWS__
     // Initialize from the implicitly available Unicode command line.
     void MSWInitialize();