In constExpr(), where code incorrectly assumed conversions to int or
uint were implicit, make them explicit.
In classEnum(), don't test bitwise operators between QFlags and
int/uint when QT_TYPESAFE_FLAGS is in effect.
Pick-to: 6.3
Fixes: QTBUG-101294
Change-Id: If119bf56dd12778f7231a9e76293c76e75354809
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>