[clang] NFCI: Clean up `CompilerInstance::create{File,Source}Manager()` (#160748)
The `CompilerInstance::createSourceManager()` function currently accepts
the `FileManager` to be used. However, all clients call
`CompilerInstance::createFileManager()` prior to creating the
`SourceManager`, and it never makes sense to use a `FileManager` in the
`SourceManager` that's different from the rest of the compiler. Passing
the `FileManager` explicitly is redundant, error-prone, and deviates
from the style of other `CompilerInstance` initialization APIs.
This PR therefore removes the `FileManager` parameter from
`createSourceManager()` and also stops returning the `FileManager`
pointer from `createFileManager()`, since that was its primary use. Now,
`createSourceManager()` internally calls `getFileManager()` instead.
GitOrigin-RevId: b86ddae1da651f921125a9864b45a5b11bc3b1c0
2 files changed
