[clang-tools-extra] [clang-apply-replacements] Deduplicate Implementation of `collectReplacementsFromDirectory` (NFC) (PR #78630)

[Daniil Dudkin via cfe-commits]

unterumarmung wrote:

The Windows build in the CI is stuck. The change is pretty trivial and doesn't use any features that cannot be found in C++98. So, we can skip the Windows check.

https://github.com/llvm/llvm-project/pull/78630