Revert "Add support for reading multi string values to wxRegKey."

Reverts r78136 (see #15727) because the multi-string values in Windows
registry are actually not "name=value" pairs at all but just NUL-separated
strings and the API provided for reading them was inappropriate.

Also see #16719.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@78326 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/msw/registry.h

@@ -205,10 +205,6 @@ public:
   bool  SetValue(const wxString& szValue, const wxMemoryBuffer& buf);
     // return the binary value
   bool  QueryValue(const wxString& szValue, wxMemoryBuffer& buf) const;
-    // return multiple strings
-  bool  QueryValue(const wxString& szValue,
-                   wxArrayString& names,
-                   wxArrayString& values) const;
 
   // query existence of a key/value
     // return true if value exists