bpo-40268: Remove a few pycore_pystate.h includes (GH-19510)

diff --git a/Python/frozenmain.c b/Python/frozenmain.c
index 508721b..dd04d60 100644
--- a/Python/frozenmain.c
+++ b/Python/frozenmain.c
@@ -2,7 +2,7 @@
 /* Python interpreter main program for frozen scripts */
 
 #include "Python.h"
-#include "pycore_pystate.h"
+#include "pycore_runtime.h"  // _PyRuntime_Initialize()
 #include <locale.h>
 
 #ifdef MS_WINDOWS