[clang] [llvm] [OffloadBundler] Bound compressed bundles by header size, not magic scan (PR #205587)

[via llvm-commits]

michaelselehov wrote:

@nikic @jhuber6 thank you. I'll work on the three stacked PRs: dedup Clang/LLVM stuff, then pin everything to LE, then finally fix the chunks detection by FileSize.
@david-salinas are you fine with the plan?

https://github.com/llvm/llvm-project/pull/205587