[clang] [clang] Fix sorting module headers (PR #73146)

[David Blaikie via cfe-commits]

dwblaikie wrote:

> Splitting it wouldn't help with bisect, as we would continue having a broken commit.

Not sure I understand - presumably this bug has existed for a while, separate from the qsort issue? So fixing it separately seems good so that patches do one thing clearly - makes it easy to review, easy to identify root causes more narrowly, easy to revert, etc.

https://github.com/llvm/llvm-project/pull/73146