Do not notify about property changes if the value hasn't changed

After 2ffb91ac59 we manually call notify()
for QObjectCompatProperties. Currently we always call it when setting
values to compat properties, even if the value hasn't actually changed.
Fixed to call notify() only if the value is being changed.

Task-number: QTBUG-85520
Change-Id: I385db84c4009c45406e204b96e0e37ce5fa8882b
Reviewed-by: Andreas Buhr <andreas.buhr@qt.io>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

src/corelib/animation/qpauseanimation.cpp

@@ -129,8 +129,13 @@ void QPauseAnimation::setDuration(int msecs)
         return;
     }
     Q_D(QPauseAnimation);
-    d->duration.setValue(msecs);
-    d->duration.notify();
+
+    if (msecs != d->duration) {
+        d->duration = msecs;
+        d->duration.notify();
+    } else {
+        d->duration.removeBindingUnlessInWrapper();
+    }
 }
 
 QBindable<int> QPauseAnimation::bindableDuration()

src/corelib/kernel/qtimer.cpp

@@ -257,9 +257,11 @@ void QTimer::start()
 void QTimer::start(int msec)
 {
     Q_D(QTimer);
+    const bool intervalChanged = msec != d->inter;
     d->inter.setValue(msec);
     start();
-    d->inter.notify();
+    if (intervalChanged)
+        d->inter.notify();
 }
 
 
@@ -753,6 +755,7 @@ QBindable<bool> QTimer::bindableSingleShot()
 void QTimer::setInterval(int msec)
 {
     Q_D(QTimer);
+    const bool intervalChanged = msec != d->inter;
     d->inter.setValue(msec);
     if (d->id != INV_TIMER) {                        // create new timer
         QObject::killTimer(d->id);                        // restart timer
@@ -761,7 +764,8 @@ void QTimer::setInterval(int msec)
         // as timer state actually does not change
     }
 
-    d->inter.markDirty();
+    if (intervalChanged)
+        d->inter.markDirty();
 }
 
 int QTimer::interval() const

src/gui/image/qmovie.cpp

@@ -929,8 +929,12 @@ void QMovie::setSpeed(int percentSpeed)
     Q_D(QMovie);
     if (!d->speed && d->movieState == Running)
         d->nextImageTimer.start(nextFrameDelay());
-    d->speed.setValue(percentSpeed);
-    d->speed.notify();
+    if (percentSpeed != d->speed) {
+        d->speed = percentSpeed;
+        d->speed.notify();
+    } else {
+        d->speed.removeBindingUnlessInWrapper();
+    }
 }
 
 int QMovie::speed() const