[analyzer] Introduce statistics for the total number of visited basic blocks

[xazax.hun]

I like the idea of having more statistics. Moreover, due to the fact that we output the percent of reachable basic blocks as an integer, it was really hard to get precise coverage data. This addition will help in this regard.

lib/StaticAnalyzer/Frontend/AnalysisConsumer.cpp

 static std::unique_ptr<ExplodedNode::Auditor> CreateUbiViz();
 
 STATISTIC(NumFunctionTopLevel, "The # of functions at top level.");
 STATISTIC(NumFunctionsAnalyzed,
                       "The # of functions and blocks analyzed (as top level "
                       "with inlining turned on).");
 STATISTIC(NumBlocksInAnalyzedFunctions,
                       "The # of basic blocks in the analyzed functions.");
+STATISTIC(NumVisitedBlocksInAnalyzedFunctions,
+          "The # of visited basic blocks in the analyzed functions.");
 STATISTIC(PercentReachableBlocks, "The % of reachable basic blocks.");
 STATISTIC(MaxCFGSize, "The maximum number of basic blocks in a function.");
 
 //===----------------------------------------------------------------------===//
 // Special PathDiagnosticConsumers.
 //===----------------------------------------------------------------------===//
 
 void ento::createPlistHTMLDiagnosticConsumer(AnalyzerOptions &AnalyzerOpts,
void AnalysisConsumer::HandleTranslationUnit(ASTContext &C) {
   // side-effects in PathDiagnosticConsumer's destructor. This is required when
   // used with option -disable-free.
   Mgr.reset();
 
   if (TUTotalTimer) TUTotalTimer->stopTimer();
 
   // Count how many basic blocks we have not covered.
   NumBlocksInAnalyzedFunctions = FunctionSummaries.getTotalNumBasicBlocks();
+  NumVisitedBlocksInAnalyzedFunctions =
+      FunctionSummaries.getTotalNumVisitedBasicBlocks();
   if (NumBlocksInAnalyzedFunctions > 0)
     PercentReachableBlocks =
       (FunctionSummaries.getTotalNumVisitedBasicBlocks() * 100) /
         NumBlocksInAnalyzedFunctions;
 
 }
 
 std::string AnalysisConsumer::getFunctionName(const Decl *D) {