PR #12438: [XLA:GPU] add force inline option to get better llvm splits
PR #12438: [XLA:GPU] add force inline option to get better llvm splits

Imported from GitHub PR https://github.com/openxla/xla/pull/12438

Add option to XLA to enforce inlining before llvm splitModule or set preserveLocals=False to get more balanced splits in parallel compilation case.

Some data of GPT3 5B model with different setting:
```
Compilation: TSL:XlaCompile:#module=pjit__wrapped_step_fn,program_id=24#: 3.754429084s (parallel + inline) runtime: 1.0s
Compilation: TSL:XlaCompile:#module=pjit__wrapped_step_fn,program_id=24#: 4.676450341s (parallel + no inline) runtime: 1.0s
Compilation: TSL:XlaCompile:#module=pjit__wrapped_step_fn,program_id=24#: 3.051018704s (parallel + perserve_local=False) runtime: 1.4s
Compilation: TSL:XlaCompile:#module=pjit__wrapped_step_fn,program_id=24#: 4.862938161s (serial) runtime: 1.0s
```

However, the runtime per step of perserve_locals=False vs other three setup is 1.4s vs 1.0s.
Copybara import of the project:

--
5f61718691d265c8609a89dc2349b1362045f7c5 by Cjkkkk <ske@nvidia.com>:

add force inline and no preserve local option to get better llvm splits

--
f32419eb792206de332be481bc59650c9d37a564 by Cjkkkk <ske@nvidia.com>:

remove preserveLocals option

Merging this change closes #12438

FUTURE_COPYBARA_INTEGRATE_REVIEW=https://github.com/openxla/xla/pull/12438 from Cjkkkk:force_inline_before_split f32419eb792206de332be481bc59650c9d37a564
