[llvm] Reland: "[Exegesis] Add the ability to dry-run the measurement phase (#121991)" (PR #122775)

[via llvm-commits]

Prabhuk wrote:

We are seeing MAC test failures as well in Fuchsia toolchain builders:

https://luci-milo.appspot.com/ui/p/fuchsia/builders/toolchain.ci/clang-host-mac-x64/b8725747943317383073/overview


https://github.com/llvm/llvm-project/pull/122775