[llvm] [libsycl] Add lit configuration files and basic test (PR #177407)

[Dmitry Vodopyanov via llvm-commits]

================
@@ -0,0 +1,122 @@
+// REQUIRES: any-device
+// RUN: %clangxx %sycl_options %s -o %t.out
+// RUN: %t.out
+//
+// Tests platform::get_devices for each device type.
+
+#include <sycl.hpp>
+
+#include <algorithm>
+#include <iostream>
+
+std::string BackendToString(sycl::backend Backend) {
+  switch (Backend) {
+  case sycl::backend::opencl:
+    return "opencl";
+  case sycl::backend::level_zero:
+    return "level_zero";
+  case sycl::backend::cuda:
+    return "cuda";
+  case sycl::backend::hip:
+    return "hip";
+  default:
+    return "unknown";
+  }
+}
+
+std::string DeviceTypeToString(sycl::info::device_type DevType) {
+  switch (DevType) {
+  case sycl::info::device_type::all:
+    return "device_type::all";
+  case sycl::info::device_type::cpu:
+    return "device_type::cpu";
+  case sycl::info::device_type::gpu:
+    return "device_type::gpu";
+  case sycl::info::device_type::accelerator:
+    return "device_type::accelerator";
+  case sycl::info::device_type::custom:
+    return "device_type::custom";
+  case sycl::info::device_type::automatic:
+    return "device_type::automatic";
+  case sycl::info::device_type::host:
+    return "device_type::host";
+  default:
+    return "UNKNOWN";
----------------
dm-vodopyanov wrote:

nit (to be consistent with BackendToString func):
```suggestion
    return "unknown";
```

https://github.com/llvm/llvm-project/pull/177407