gh-115914: minor cleanup: simplify filename_obj assignment in PyRun_AnyFileExFlags (gh-115916)

This simplifies the code: less lines, easier to read. Logically equivalent, as any compiler likely already determined.

Author: gorsing

Python/pythonrun.c

@@ -89,17 +89,14 @@ int
 PyRun_AnyFileExFlags(FILE *fp, const char *filename, int closeit,
                      PyCompilerFlags *flags)
 {
-    PyObject *filename_obj;
+    PyObject *filename_obj = NULL;
     if (filename != NULL) {
         filename_obj = PyUnicode_DecodeFSDefault(filename);
         if (filename_obj == NULL) {
             PyErr_Print();
             return -1;
         }
     }
-    else {
-        filename_obj = NULL;
-    }
     int res = _PyRun_AnyFileObject(fp, filename_obj, closeit, flags);
     Py_XDECREF(filename_obj);
     return res;