Arm backend: Add util for symbolic range eval

[oscarandersson8218]

Adds util for computing a value range from a symbolic expression.

cc @digantdesai @freddan80 @per @zingo @mansnils @Sebastian-Larsson @robell

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/19108

• 📄 Preview Python docs built from this PR

Note: Links to docs will display an error until the docs builds have been completed.

❗ 1 Active SEVs

There are 1 currently active SEVs. If your PR is affected, please view them below:

• Rolling out OSDC (ARC) runners on pull & trunk workflows in PyTorch main

❌ 2 Cancelled Jobs, 3 Unrelated Failures

As of commit b947aa0 with merge base eef7921 ():

CANCELLED JOBS - The following jobs were cancelled. Please retry:

• pull / test-sqnr-static-llm-qnn-linux (smollm2_135m) / linux-job (gh)
  ##[error]The operation was canceled.
• trunk / test-models-macos-coreml (dl3) / macos-job (gh)
  ##[error]The operation was canceled.

BROKEN TRUNK - The following jobs failed but were present on the merge base:

👉 Rebase onto the `viable/strict` branch to avoid these failures

• pull / unittest / windows / windows-job (gh) (trunk failure)
  ##[error]The operation was canceled.
• pull / unittest-editable / windows / windows-job (gh) (trunk failure)
  ##[error]The operation was canceled.
• trunk / unittest-release / windows / windows-job (gh) (trunk failure)
  ##[error]The operation was canceled.

This comment was automatically generated by Dr. CI and updates every 15 minutes.

[zingo]

OK to merge just make sure needed buck2 files are updated if changes are needed or add a comment if you think no change is needed.

[oscarandersson8218]

OK to merge just make sure needed buck2 files are updated if changes are needed or add a comment if you think no change is needed.

Should be ok as the new pass is covered by the passes/TARGETS glob, and the new test is covered by the passes/test*.py glob in backends/arm/test/targets.bzl.