tdf#119922, sanitize the point count when extrapolate is used

Change-Id: Iec5e591f51ab13efa4b014b82df213e91eb5b793
Reviewed-on: https://gerrit.libreoffice.org/60949
Tested-by: Jenkins
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>

chart2/source/view/charttypes/VSeriesPlotter.cxx

@@ -1183,6 +1183,8 @@ void VSeriesPlotter::createRegressionCurvesShapes( VDataSeries const & rVDataSer
             fMinX -= aExtrapolateBackward;
 
             fPointScale = (fMaxX - fMinX) / (fChartMaxX - fChartMinX);
+            // sanitize the value, tdf#119922
+            fPointScale = std::min(fPointScale, 1000.0);
         }
 
         xCalculator->setRegressionProperties(aDegree, bForceIntercept, aInterceptValue, aPeriod);