Move test_assets and logits generation script inside tests directory

[SurbhiJainUSC]

Description

This PR refactors tests assets based on https://screenshot.googleplex.com/574uqLTPrQy8FuN

• Move src/MaxText/test_assets to tests/assets/golden_logits
• Move golden data generation scripts inside src/MaxText/scratch_code/ to tests/assets/logits_generation
• Updated Github CI workflows to reflect this new tests assets path
• Updated Dockerfiles to reflect this new tests assets path

Tests

Unit/integ tests

Checklist

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• I have performed a self-review of my code. For an optional AI review, add the gemini-review label.
• I have necessary comments in my code, particularly in hard-to-understand areas.
• I have run end-to-end tests tests and provided workload links above if applicable.
• 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.

[github-actions]

🤖 Hi @SurbhiJainUSC, I've received your request, and I'm working on it now! You can track my progress in the logs for more details.

[github-actions]

## 📋 Review Summary

This pull request effectively refactors the project structure by moving test assets and logits generation scripts into the tests directory. The changes are consistent and well-executed across the codebase, improving the separation between source code and test data.

🔍 General Feedback

• The paths in CI workflows, Dockerfiles, and test files have been updated correctly to reflect the new file locations.
• I've pointed out a minor inconsistency in the default path construction for MAXTEXT_TEST_ASSETS_ROOT in a couple of end-to-end test scripts. Using MAXTEXT_REPO_ROOT as the base would be more consistent with the rest of the changes.

Overall, this is a solid refactoring that improves the project's organization.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[hengtaoguo]

Could you also update these two lines regarding the test_image.jpg/test_video.mp4 path? This is the most critical one at the moment. Thanks!

maxtext/tests/check_qwen3_embedding_vs_reference.py

Lines 534 to 535 in 111cb6b

	self.image_path = os.path.join(MAXTEXT_REPO_ROOT, "src", "MaxText", "test_assets", "test_image.jpg")
	self.video_path = os.path.join(MAXTEXT_REPO_ROOT, "src", "MaxText", "test_assets", "test_video.mp4")

There might be some other places referencing these static assets too:

https://github.com/search?q=repo%3AAI-Hypercomputer%2Fmaxtext+test_image.jpg&type=code

[SurbhiJainUSC]

Could you also update these two lines regarding the test_image.jpg/test_video.mp4 path? This is the most critical one at the moment. Thanks!

maxtext/tests/check_qwen3_embedding_vs_reference.py

Lines 534 to 535 in 111cb6b

	self.image_path = os.path.join(MAXTEXT_REPO_ROOT, "src", "MaxText", "test_assets", "test_image.jpg")
	self.video_path = os.path.join(MAXTEXT_REPO_ROOT, "src", "MaxText", "test_assets", "test_video.mp4")

There might be some other places referencing these static assets too:

https://github.com/search?q=repo%3AAI-Hypercomputer%2Fmaxtext+test_image.jpg&type=code

Thank you Hengtao, updated.