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

[Qiongsi Wu via cfe-commits]

qiongsiwu wrote:

Or maybe it makes more sense to set the working directory to SYSROOT, or to the input header's path? 

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