Add optimization to remove redundant label

Add additional CFG optimization to remove redundant label.

Author: kychendev

visa/FlowGraph.cpp

@@ -848,6 +848,7 @@ void FlowGraph::constructFlowGraph(INST_LIST &instlist) {
 
   setPhysicalPredSucc();
   removeUnreachableBlocks(funcInfoHashTable);
+  removeRedundantLabels();
 
   pKernel->dumpToFile("after.RemoveUnreachableBlocks");