[JAX] Add experimental internal used THD(packed) fused attn API

[zlsh80826]

Description

This PR exposes underly THD format API to JAX side and wrap it to be supported on multi-gpus.

Fixes # (issue)

Type of change

• [ ] Documentation change (change only to the documentation, either a fix or a new content)
• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] Infra/Build change
• [ ] Code refractor

Changes

• Unify fused_attn_qkvpacked, fused_attn_kvpacked, fused_attn to be a single function
• Add experimental fused_attn_thd API with the corresponding unit tests, this API requires users to configure a static max_segments_per_seq argument and ensure the "number of segments" in a seqeunce less and equal than this value
  • workspace memory consumptions: ~batch_size max_sequence_length max_segments_per_seq * num_heads
• Reduce test_fused_attn runtime
  • Test only 1 FP16 shape
  • Disable forward tests (backward tests include forward, we kept forward for the development and debugging).

Checklist:

• [x] I have read and followed the contributing guidelines
• [x] The functionality is complete
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings
• [x] I have added tests that prove my fix is effective or that my feature works
• [x] New and existing unit tests pass locally with my changes

[zlsh80826]

/te-ci jax

[zlsh80826]

/te-ci jax