tdf#151456: AnimatedImages in Basic Dialog : StepTime is ignored

2 problems here
1) Regression on test of "pThrobber" since 51e97b2ffd
toolkit: first cut at switching to VclPtr.

2) as the author of the bug "Jurassik Pork" indicated,
"mnStepTime" wasn't used after having been used in ctr of Throbber
Thank you to him for the suggestion!

Change-Id: I0d1a53738035c3e822ea84d5972363dd9d0b5d8d
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/160771
Tested-by: Jenkins
Reviewed-by: Julien Nabet <serval2412@yahoo.fr>

toolkit/source/awt/animatedimagespeer.cxx

@@ -182,7 +182,7 @@ namespace toolkit
         SolarMutexGuard aGuard;
 
         VclPtr<Throbber> pThrobber = GetAsDynamic<Throbber>();
-        if ( pThrobber )
+        if ( !pThrobber )
         {
             VCLXWindow::setProperty( i_propertyName, i_value );
             return;

vcl/source/control/throbber.cxx

@@ -152,6 +152,7 @@ void Throbber::initImages()
 
 void Throbber::start()
 {
+    maWaitTimer.SetTimeout(mnStepTime);
     maWaitTimer.Start();
 }