[compiler-rt] [TSan] Clarify and enforce shadow end alignment (PR #144648)

[Kunqiu Chen via llvm-commits]

Camsyn wrote:

> It looks like this broke a test in iOS CI: https://ci.swift.org/job/llvm.org/job/clang-san-iossim/9785/testReport/junit/ThreadSanitizer-x86_64-iossim/ThreadSanitizer-x86_64-iossim/munmap_clear_shadow_c/

I got 404 when accessing this link. Could you paste the relevant test output to help me debug the issue?

https://github.com/llvm/llvm-project/pull/144648