Backport fix from default branch for ./python -R -Wd where hash('d') would not

have gotten randomized.

Modules/main.c

@@ -396,6 +396,12 @@ Py_Main(int argc, char **argv)
 
         case 'W':
             PySys_AddWarnOption(_PyOS_optarg);
+            /* Extremely obscure hack: if _PyOS_optarg was one character,
+               PyString_FromString in PySys_AddWarnOption will try to intern
+               it. This is bad because hash randomization has not been setup
+               yet, so the string will get the wrong hash. The following call
+               will cause all the cached characters to be released. */
+            PyString_Fini();
             break;
 
         case 'R':