XLA pin downgrade to 20230825 (#5592)
Summary:
The 20230826 version contains https://github.com/openxla/xla/commit/3b8a5398ea9e479311d5c0c34bb1ae255551f9d4
whch regresses our LLaMA2 GSPMD training benchmark. Let's rollback to version
before it.
Test Plan:
CI.
