test/cfg/std.cpp fix 'make checkcfg', std::vector needs to have <vector> #included

test/cfg/std.cpp

@@ -25,6 +25,7 @@
 #include <cinttypes>
 #include <istream>
 #include <fstream>
+#include <vector>
 
 void bufferAccessOutOfBounds(void)
 {
@@ -3257,4 +3258,4 @@ void stdvector()
     std::vector<int> v;
     // cppcheck-suppress ignoredReturnValue
     v.size();
-}
+}