Re-merge `A few updates around "transcript"` (#92843) (#94067)

Problematic PR: https://github.com/llvm/llvm-project/pull/92843
Reverted by: https://github.com/llvm/llvm-project/pull/94088



The first PR added a test which fails in Linux builds (see the last few
comments there).
This PR contains all the changes in the first PR, plus the fix to the
said test.

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Co-authored-by: Roy Shi <royshi@meta.com>