Suppress may_unwind.rs rust test

While upstream figures out what to do (https://github.com/llvm/llvm-project/pull/144745#issuecomment-3212128246).

This is just a test issue.

Bug: 436652831
Change-Id: I7a215cf0d6063cbd0070df016587296fc02c7209
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6872241
Reviewed-by: Alan Zhao <ayzhao@google.com>
Commit-Queue: Alan Zhao <ayzhao@google.com>
Commit-Queue: Arthur Eubanks <aeubanks@google.com>
Auto-Submit: Arthur Eubanks <aeubanks@google.com>
Cr-Commit-Position: refs/heads/main@{#1504726}