[clang] [clang][DependencyScanning] Move driver-command logic for by-name scanning into DependencyScanningTool (PR #171238)

[Qiongsi Wu via cfe-commits]

https://github.com/qiongsiwu approved this pull request.

This overall looks great! Thanks so much for working on it! I have only two nits and a question.

https://github.com/llvm/llvm-project/pull/171238