Fix rngs used for training

[xibinliu]

Description

Fix rngs used for training.
Also fix the unit tests to make them run in different tpu VMs

Tests

Run a training successfully.

Checklist

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• I have made or will make corresponding changes to the doc if needed, including adding new documentation pages to the relevant Table of Contents (toctree directive) as explained in our documentation.

[codecov]

Codecov Report

❌ Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/MaxText/maxtext_utils.py	0.00%	1 Missing ⚠️

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