Performance : Cache result of some string manipulation functions

These functions get called quite often, and popped up based on profiling.

ApplicationLibCode/Application/RiaApplication.cpp

@@ -31,6 +31,7 @@
 #include "RiaTextStringTools.h"
 #include "RiaVersionInfo.h"
 #include "RiaViewRedrawScheduler.h"
+#include "RiaWellNameComparer.h"
 
 #include "ExportCommands/RicSnapshotAllViewsToFileFeature.h"
 #include "HoloLensCommands/RicHoloLensSessionManager.h"
@@ -782,6 +783,8 @@ void RiaApplication::closeProject()
     m_project->close();
     m_commandQueue.clear();
 
+    RiaWellNameComparer::clearCache();
+
     onProjectClosed();
 
     caf::PdmUiModelChangeDetector::instance()->reset();