adjustment: sanity-check values when setting them

It's not enough to sanitize values when starting an animation, as the
adjustment can reconfigure itself while the animation runs.
So as a simple way to handle this, we sanitize every value right before
setting it, too.

In the future we might also want to look at sanitizing start/end values
of the animation.

Fixes #5763

gtk/gtkadjustment.c

@@ -434,6 +434,8 @@ adjustment_set_value (GtkAdjustment *adjustment,
 {
   GtkAdjustmentPrivate *priv = gtk_adjustment_get_instance_private (adjustment);
 
+  value = gtk_adjustment_sanitize_value (adjustment, value);
+
   if (priv->value != value)
     {
       priv->value = value;