[RF] Increment value reset counter also in RooRealVar::setValFast()

There is a `RooRealVar::setValFast()` method that behaves like
`RooRealVar::setVal()` but without the boundary check, for internal
RooFit use in the `RooRealVar::setBin()` method.

It's important to also increment the value reset counter in this method,
so that recomputations in the RooFit::Evaluator will be triggered
correctly.

Thanks to @PetroZarytskyi for finding this!

Author: guitargeek

roofit/roofitcore/inc/RooRealVar.h

@@ -138,8 +138,14 @@ class RooRealVar : public RooAbsRealLValue {
   static bool _printScientific ;
   static Int_t  _printSigDigits ;
 
-  void setValFast(double value) override { _value = value ; setValueDirty() ; }
-
+   void setValFast(double value) override
+   {
+      if (_value != value) {
+         ++_valueResetCounter;
+      }
+      _value = value;
+      setValueDirty();
+   }
 
   double evaluate() const override { return _value ; } // dummy because we overloaded getVal()
   void copyCache(const RooAbsArg* source, bool valueOnly=false, bool setValDirty=true) override ;