[llvm] [DWARF] Emit a worst-case prologue_end flag for pathological inputs (PR #107849)

[Orlando Cazalet-Hyams via llvm-commits]

OCHyams wrote:

> Sorry for the bother; fixed in https://github.com/llvm/llvm-project/commit/251958f3570730f58d1337ac6d00f03ee6a839fe. @OCHyams could you do some post-commit review on that?

LGTM (commented there too)

https://github.com/llvm/llvm-project/pull/107849