[libFuzzer] DFT: when dumping coverage, also dump the total number of instrumented blocks in a function; update merge_data_flow.py to merge coverage

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk/lib/fuzzer@360272 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/FuzzerDataFlowTrace.cpp b/FuzzerDataFlowTrace.cpp
index 5ae7510..604fe15 100644
--- a/FuzzerDataFlowTrace.cpp
+++ b/FuzzerDataFlowTrace.cpp
@@ -52,6 +52,8 @@
     // Printf("=== %s\n", Name.c_str());
     std::ifstream IF(SF.File);
     while (std::getline(IF, L, '\n')) {
+      if (!L.empty() && L[0] == 'C')
+        continue; // Ignore coverage.
       size_t SpacePos = L.find(' ');
       if (SpacePos == std::string::npos)
         return ParseError("no space in the trace line");