Remove non-portable directory separator from test

Author: dwblaikie

clang/test/CodeGenCXX/debug-info-simple-template-names.cpp

@@ -54,7 +54,7 @@ void f() {
   struct {
   } unnamed_struct;
   f1<decltype(unnamed_struct)>();
-  // CHECK: !DISubprogram(name: "f1<(unnamed struct at {{.*}}CodeGenCXX/debug-info-simple-template-names.cpp:[[# @LINE - 3]]:3)>",
+  // CHECK: !DISubprogram(name: "f1<(unnamed struct at {{.*}}debug-info-simple-template-names.cpp:[[# @LINE - 3]]:3)>",
   enum {} unnamed_enum;
   f1<decltype(unnamed_enum)>();
   // CHECK: !DISubprogram(name: "f1<(unnamed enum at {{.*}}debug-info-simple-template-names.cpp:[[# @LINE - 2]]:3)>",