Try silence cid#1371124 ("Operands don't affect result")

...where Coverity doesn't reveal which instantiation of the templated code it is
complaining about, but it must be ScRefFlags (sc/inc/address.hxx), which has
underlying type sal_uInt16 and a mask of 0xFFFF.

Change-Id: If0abd195885acdffb3c61cdab88d7a2c87c00c4f

include/o3tl/typed_flags_set.hxx

@@ -79,7 +79,11 @@ struct is_typed_flags {
         {
 #if !HAVE_CXX11_CONSTEXPR || HAVE_CXX14_CONSTEXPR
             assert(detail::isNonNegative(value));
-            assert((value & ~M) == 0);
+            assert(
+                static_cast<typename std::underlying_type<E>::type>(~M) == 0
+                    // avoid "operands don't affect result" warnings when M
+                    // covers all bits of the underlying type
+                || (value & ~M) == 0);
 #endif
         }