Fix asan error

Author: fangyi-zhou

clang/include/clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h

@@ -101,6 +101,11 @@ class SymbolConjured : public SymbolData {
 
   // It might return null.
   const Stmt *getStmt() const {
+    if (const auto *Parent = Elem.getParent()) {
+      // Sometimes the CFG element is invalid, avoid dereferencing it.
+      if (Elem.getIndexInBlock() >= Parent->size())
+        return nullptr;
+    }
     switch (Elem->getKind()) {
     case CFGElement::Initializer:
       if (const auto *Init = Elem->castAs<CFGInitializer>().getInitializer()) {