enable ut test for xpu devices

[DiweiSun]

(Please be kindly informed that this PR encompasses a large scope. It will be split into smaller PRs as requested.)

This PR is to enable Sglang UTs on XPU. What we do in this PR:

1. Enabling multi-hardware config in test/runners.py
2. Enabling multi-hardware config in test/test_utils.py
3. Enabling multi-hardware on test_*.py as required.

How to Run UTs on XPU:
Apply this PR/diff on Sglang main, and then build sglang env via docker/Dockerfile.xpu.
Pypi Packages might be required by some cases and shall be manually installed:
flashinfer-python
sentencepiece
ray
accelerate
nest-asyncio

pytest -v test_*.py