Fix pdb-type-server-simple test on non-Windows

Assume that the LF_TYPESERVER2 record contains Windows-style paths.  In
any case, 'sys::path::filename(Path, Style::windows)' will work on
Unix-style paths.

llvm-svn: 308241
diff --git a/lld/COFF/PDB.cpp b/lld/COFF/PDB.cpp
index 54dc1fa..89462da 100644
--- a/lld/COFF/PDB.cpp
+++ b/lld/COFF/PDB.cpp
@@ -255,7 +255,8 @@
     StringRef LocalPath =
         !File->ParentName.empty() ? File->ParentName : File->getName();
     SmallString<128> Path = sys::path::parent_path(LocalPath);
-    sys::path::append(Path, sys::path::filename(TS.getName()));
+    sys::path::append(
+        Path, sys::path::filename(TS.getName(), sys::path::Style::windows));
     ExpectedSession = tryToLoadPDB(TS.getGuid(), Path);
   }
   if (auto E = ExpectedSession.takeError())