[clang] [clang modules] Setting `DebugCompilationDir` when it is safe to ignore current working directory (PR #128446)

[Qiongsi Wu via cfe-commits]

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@@ -492,8 +492,23 @@ static std::string getModuleContextHash(const ModuleDeps &MD,
   auto &FSOpts = const_cast<FileSystemOptions &>(CI.getFileSystemOpts());
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qiongsiwu wrote:

I refactored the code a bit in this PR and we don't use `const_cast` any more. 

https://github.com/llvm/llvm-project/pull/128446