Fix another warning when comparing size_t and qsizetype

Amends 07f7ed2bad.

Change-Id: I0644e47e8e9ccd0bcaf074adf99e7481c692b5c1
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

tests/auto/tools/moc/tst_moc.cpp

@@ -2504,7 +2504,7 @@ void tst_Moc::cxx11Enums()
         QCOMPARE(size_t(metaType.sizeOf()), sizeof(char));
         QCOMPARE(isUnsigned, !std::is_signed_v<char>);
     } else if (isScoped) {
-        QCOMPARE(metaType.sizeOf(), sizeof(int));
+        QCOMPARE(size_t(metaType.sizeOf()), sizeof(int));
         QCOMPARE(isUnsigned, !std::is_signed_v<int>);
     } else {
         // underlying type is implementation defined