[Inference/Kernel] Remove unnecessary float4_ and rename float8_ to float8

[SunflowerAries]

📌 Checklist before creating the PR

• [ ] I have created an issue for this PR for traceability
• [ ] The title follows the standard format: [doc/gemini/tensor/...]: A concise description
• [ ] I have added relevant tags if possible for us to better distinguish different PRs
• [ ] I have installed pre-commit: pip install pre-commit && pre-commit install

🚨 Issue number

Link this PR to your issue with words like fixed to automatically close the linked issue upon merge

e.g. fixed #1234, closed #1234, resolved #1234

📝 What does this PR do?

Summarize your work here. if you have any plots/diagrams/screenshots/tables, please attach them here.

💥 Checklist before requesting a review

• [ ] I have linked my PR to an issue (instruction)
• [ ] My issue clearly describes the problem/feature/proposal, with diagrams/charts/table/code if possible
• [ ] I have performed a self-review of my code
• [ ] I have added thorough tests.
• [ ] I have added docstrings for all the functions/methods I implemented

⭐️ Do you enjoy contributing to Colossal-AI?

• [ ] 🌝 Yes, I do.
• [ ] 🌚 No, I don't.

Tell us more if you don't enjoy contributing to Colossal-AI.

[Courtesy-Xs]

Add a test pic plz