[llvm] [libsycl] Add sycl::queue stub (PR #184110)

[Sergey Semenov via llvm-commits]

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@@ -106,3 +106,5 @@ TODO for added SYCL classes
 
 * device selection: to add compatibility with old SYCL 1.2.1 device selectors, still part of SYCL 2020 specification
 * ``context``: to implement get_info, properties & public constructors once context support is added to liboffload
+* ``queue``: to implement USM methods, to implement synchronization methods, to implement submit & copy with accessors (low priority), get_info & properties, ctors that accepts context (blocked by lack of liboffload support)
+* ``property_list``: to fully implement and integrate to existing SYCL runtime classes supporting it
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sergey-semenov wrote:

```suggestion
* ``property_list``: to fully implement and integrate with existing SYCL runtime classes supporting it
```

https://github.com/llvm/llvm-project/pull/184110