[clang] [clang][DependencyScanning] Implementation of `CompilerInstanceWithContext` to Improve By-Name Queries (PR #164345)

[Qiongsi Wu via cfe-commits]

qiongsiwu wrote:

I added back `DependencyScanningTool::getModuleDependencies` so Swift can still use it. This way, we can land this PR independently from Swift. I will remove it as soon as Swift adopts the new APIs. 

https://github.com/llvm/llvm-project/pull/164345