Issue #19512: add some common identifiers to only create common strings once,

instead of creating temporary Unicode string objects

Add also more identifiers in pythonrun.c to avoid temporary Unicode string
objets for the interactive interpreter.

Python/traceback.c

@@ -169,7 +169,7 @@ _Py_FindSourceFile(PyObject *filename, char* namebuf, size_t namelen, PyObject *
         tail++;
     taillen = strlen(tail);
 
-    syspath = PySys_GetObject("path");
+    syspath = _PySys_GetObjectId(&_PyId_path);
     if (syspath == NULL || !PyList_Check(syspath))
         goto error;
     npath = PyList_Size(syspath);