### What changes were proposed in this pull request?

This PR aims to upgrade `swift-system` to 1.7.5.

### Why are the changes needed?

To bring the latest bug fixes.

- https://github.com/apple/swift-system/releases/tag/1.7.5
  - https://github.com/apple/swift-system/pull/355

### Does this PR introduce _any_ user-facing change?

No.

### How was this patch tested?

Pass the CIs.

### Was this patch authored or co-authored using generative AI tooling?

Generated-by: Claude Fable 5

Closes #440 from dongjoon-hyun/SPARK-58254.

Authored-by: Dongjoon Hyun <dongjoon@apache.org>
Signed-off-by: Dongjoon Hyun <dongjoon@apache.org>