Silence warnings from unused variables

Use them, or replace them with existing constants.

Pick-to: 6.5
Change-Id: I808028296305e15b68aecb1f961ba6a85b8e9cc7
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Øystein Heskestad <oystein.heskestad@qt.io>
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

tests/benchmarks/corelib/kernel/events/tst_bench_events.cpp

@@ -88,6 +88,7 @@ void EventsBench::noEvent()
     QBENCHMARK {
         val += tst.foo(1);
     }
+    QVERIFY(val > 0);
 }
 
 void EventsBench::sendEvent_data()

tests/benchmarks/corelib/thread/qthreadstorage/tst_bench_qthreadstorage.cpp

@@ -64,6 +64,7 @@ void tst_QThreadStorage::get()
         int *i = ts.localData();
         count += *i;
     }
+    QVERIFY(count > 0);
     ts.setLocalData(0);
 }
 

tests/benchmarks/corelib/time/qdatetime/CMakeLists.txt

@@ -10,4 +10,5 @@ qt_internal_add_benchmark(tst_bench_qdatetime
         tst_bench_qdatetime.cpp
     LIBRARIES
         Qt::Test
+        Qt::CorePrivate
 )

tests/benchmarks/corelib/time/qdatetime/tst_bench_qdatetime.cpp

@@ -6,6 +6,7 @@
 #include <QTest>
 #include <QList>
 #include <qdebug.h>
+#include <QtCore/private/qdatetime_p.h>
 
 class tst_QDateTime : public QObject
 {
@@ -67,8 +68,7 @@ private Q_SLOTS:
     void fromMSecsSinceEpochTz();
 };
 
-constexpr qint64 SECS_PER_DAY = 86400;
-constexpr qint64 MSECS_PER_DAY = 86400000;
+using namespace QtPrivate::DateTimeConstants;
 constexpr qint64 JULIAN_DAY_1 = 1721426;
 constexpr qint64 JULIAN_DAY_11 = 1725078;
 constexpr qint64 JULIAN_DAY_1890 = 2411369;