llvm-symbolizer: don't leave dangling pointers after flushing LLVMSymbolizer. Add a destructor.

llvm-svn: 185154
diff --git a/llvm/tools/llvm-symbolizer/LLVMSymbolize.cpp b/llvm/tools/llvm-symbolizer/LLVMSymbolize.cpp
index 5956416..57f34c2 100644
--- a/llvm/tools/llvm-symbolizer/LLVMSymbolize.cpp
+++ b/llvm/tools/llvm-symbolizer/LLVMSymbolize.cpp
@@ -202,6 +202,8 @@
 void LLVMSymbolizer::flush() {
   DeleteContainerSeconds(Modules);
   DeleteContainerPointers(ParsedBinariesAndObjects);
+  BinaryForPath.clear();
+  ObjectFileForArch.clear();
 }
 
 static std::string getDarwinDWARFResourceForPath(const std::string &Path) {