Address review: use wrapper functions instead of low-level accessors

Use _Py_IsCoreInitialized() in preconfig.c and Py_IsInitialized() in
Py_InitializeEx(), removing the unnecessary runtime local variable.

Thanks picnixz!

Author: gpshead

Python/preconfig.c

@@ -928,7 +928,7 @@ _PyPreConfig_Write(const PyPreConfig *src_config)
         return status;
     }
 
-    if (_PyRuntimeState_GetCoreInitialized(&_PyRuntime)) {
+    if (_Py_IsCoreInitialized()) {
         /* bpo-34008: Calling this functions after Py_Initialize() ignores
            the new configuration. */
         return _PyStatus_OK();

Python/pylifecycle.c

@@ -1505,9 +1505,8 @@ Py_InitializeEx(int install_sigs)
     if (_PyStatus_EXCEPTION(status)) {
         Py_ExitStatusException(status);
     }
-    _PyRuntimeState *runtime = &_PyRuntime;
 
-    if (_PyRuntimeState_GetInitialized(runtime)) {
+    if (Py_IsInitialized()) {
         /* bpo-33932: Calling Py_Initialize() twice does nothing. */
         return;
     }

Python/sysmodule.c

@@ -33,7 +33,6 @@ Data members:
 #include "pycore_pymath.h"        // _PY_SHORT_FLOAT_REPR
 #include "pycore_pymem.h"         // _PyMem_DefaultRawFree()
 #include "pycore_pystate.h"       // _PyThreadState_GET()
-#include "pycore_runtime.h"       // _PyRuntimeState_GetInitialized()
 #include "pycore_pystats.h"       // _Py_PrintSpecializationStats()
 #include "pycore_structseq.h"     // _PyStructSequence_InitBuiltinWithFlags()
 #include "pycore_sysmodule.h"     // export _PySys_GetSizeOf()
@@ -472,7 +471,7 @@ PySys_AddAuditHook(Py_AuditHookFunction hook, void *userData)
        PySys_AddAuditHook() can be called before Python is initialized. */
     _PyRuntimeState *runtime = &_PyRuntime;
     PyThreadState *tstate;
-    if (_PyRuntimeState_GetInitialized(runtime)) {
+    if (Py_IsInitialized()) {
         tstate = _PyThreadState_GET();
     }
     else {