Fixed crash in clang test suite.

lib/checkstl.cpp

@@ -78,6 +78,9 @@ void CheckStl::iterators()
         if (var->typeEndToken()->str() == "auto") {
             if (Token::Match(var->typeEndToken(), "auto %name% ; %name% = %var% . %name% ( )")) {
                 const Token* containertok = var->typeEndToken()->tokAt(5);
+                if (!containertok->variable())
+                    continue;
+
                 const Library::Container* container = _settings->library.detectContainer(containertok->variable()->typeStartToken());
                 if (!container)
                     continue;

test/teststl.cpp

@@ -535,6 +535,14 @@ private:
               "    auto b = x.first;\n"
               "}");
         ASSERT_EQUALS("", errout.str());
+
+        check("const CXXRecordDecl *CXXRecordDecl::getTemplateInstantiationPattern() const {\n"
+              "    if (auto *TD = dyn_cast<ClassTemplateSpecializationDecl>(this)) {\n"
+              "        auto From = TD->getInstantiatedFrom();\n"
+              "    }\n"
+              "    return nullptr;\n"
+              "}");
+        ASSERT_EQUALS("", errout.str());
     }
 
     void STLSize() {