Remove wxDECLARE_NO_COPY_CLASS from a local class in wxGrid test

Declaring the copy ctor/assignment operator for a local class without
defining them triggers MSVC warning C4822, so don't do this to avoid
unnecessary noise in the build logs (we could disable the warning or
conditionally do this for non-MSVC compilers, but it doesn't seem to be
worth doing this for a class used inside a single function and very
unlikely to be copied accidentally).

tests/controls/gridtest.cpp

@@ -850,8 +850,6 @@ void GridTestCase::WindowAsEditorControl()
         wxGridCellEditor* Clone() const wxOVERRIDE { return new TestEditor(); }
 
         wxString GetValue() const wxOVERRIDE { return "value"; }
-
-        wxDECLARE_NO_COPY_CLASS(TestEditor);
     };
 
     wxGridCellAttr* attr = new wxGridCellAttr();