Qt::totally_ordered_wrapper: specialize QTypeInfo

Simple: just inherit the payload type's (QTypeInfoMerger isn't needed,
as the sizeof totally_ordered_wrapper<P> is the same as the sizeof P).

Yes, this means Qt::totally_ordered_wrapper<P> is marked as isPointer,
but that trait is already deprecated.

Found in API-Review.

Change-Id: I4b5df08cd4891bd463d1f127c17ed5c4cd812984
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>
(cherry picked from commit 5bfb6d513c0692ba1b6621b2ff0b3207088eb742)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

src/corelib/global/qcomparehelpers.h

@@ -16,6 +16,7 @@
 
 #include <QtCore/qoverload.h>
 #include <QtCore/qttypetraits.h>
+#include <QtCore/qtypeinfo.h>
 #include <QtCore/qtypes.h>
 
 #ifdef __cpp_lib_three_way_comparison
@@ -663,6 +664,9 @@ private:
 
 } //Qt
 
+template <typename P>
+class QTypeInfo<Qt::totally_ordered_wrapper<P>> : public QTypeInfo<P> {};
+
 QT_END_NAMESPACE
 
 namespace std {