[TE/JAX] Prototype for New XLA Custom Calls with FFI

[phu0ngng]

Description

This PR introduced a prototype for converting TE/JAX custom calls to the new XLA Custom Call with FFI. These primitives are implemented with the new custom calls:

• CastTranspose
• ActLu
• DActLu

FFI Datatype with FP8 types has been added to XLA in this PR (openxla/xla#13856). All related tests passed.

WIP: Verifying that these custom calls are captured in CudaGraph.

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)
• [ ] New feature (non-breaking change which adds functionality)
• [x] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] Infra/Build change
• [ ] Code refractor

Checklist:

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