[SYCL][HIP] Add HIP support to filter selector (#5171)

This fixes the `FilterSelector/select.cpp` test of `llvm-test-suite`

Author: npmiller

sycl/source/detail/filter_selector_impl.cpp

@@ -80,6 +80,9 @@ filter create_filter(const std::string &Input) {
     } else if (Token == "cuda" && !Result.HasBackend) {
       Result.Backend = backend::ext_oneapi_cuda;
       Result.HasBackend = true;
+    } else if (Token == "hip" && !Result.HasBackend) {
+      Result.Backend = backend::ext_oneapi_hip;
+      Result.HasBackend = true;
     } else if (Token == "host") {
       if (!Result.HasBackend) {
         Result.Backend = backend::host;