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

[Fangrui Song via cfe-commits]

================
@@ -406,6 +415,15 @@ bool SpecialCaseList::parse(unsigned FileIdx, const MemoryBuffer *MB,
   bool UseGlobs = MinVersion(2);
   bool RemoveDotSlash = MinVersion(3);
   bool WarnDotSlash = MinVersion(4) && !MinVersion(5);
+  // FIXME: Improve efficiency on Windows.
----------------
MaskRay wrote:

Inefficiency should use TODO instead of FIXME

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