[clang] [llvm] Make sanitizer special case list slash-agnostic (PR #149886)

[James Y Knight via llvm-commits]

jyknight wrote:

I'm sorry I haven't yet read all the recent comments regarding technical issues with supporting both / and \, but just want to say my initial impression is that it'd be a massive overkill to force an incompatible format-change here, instead of just supporting both separators on Windows. I'll write a more informed reply later.

https://github.com/llvm/llvm-project/pull/149886