[llvm] [libsycl] extend sycl::event API with get_wait_list, wait_and_throw and default ctor (PR #205860)

[Alexey Bader via llvm-commits]

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@@ -166,14 +166,26 @@ class _LIBSYCL_EXPORT queue {
   /// exceptions.
   void wait();
 
+  /// Blocks the calling thread until all commands previously submitted to this
+  /// queue have completed. Synchronous errors are reported through SYCL
+  /// exceptions. At least all unconsumed asynchronous errors held by this queue
+  /// are passed to the appropriate async_handler.
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bader wrote:

Can we say:
```suggestion
  /// are passed to the async_handler associated with the queue.
```
?

https://github.com/llvm/llvm-project/pull/205860