[SYCL] Add test for type aliases as kernel parameter within free function kernel

[dyniols]

This PR adds new test for free function kernels extension based on test plan https://github.com/intel/llvm/blob/sycl/sycl/test-e2e/FreeFunctionKernels/test-plan.md#test-type-aliases-to-allowed-kernel-paramater-types-as-kernel-parameter

Extension spec: https://github.com/intel/llvm/blob/sycl/sycl/doc/extensions/proposed/sycl_ext_oneapi_free_function_kernels.asciidoc

It removes unused alias of type accessor<int, 1, access::mode::read_write> from sycl/test/extensions/free_function_errors.cpp

[dklochkov-emb]

I think, it is needed to add tests with C-style typedef too.

[aelovikov-intel]

I think, it is needed to add tests with C-style typedef too.

@tahonermann , do you agree? I'd expect FE's processing of them is identical and that would just bloat the test for no benefit.

[tahonermann]

I think, it is needed to add tests with C-style typedef too.

@tahonermann , do you agree? I'd expect FE's processing of them is identical and that would just bloat the test for no benefit.

typedef and using type alias declarations are represented differently in the Clang AST (using TypedefDecl vs TypeAliasDecl respectively), so I think it makes sense to exercise both. The risk of observable differences is low but not zero. I would probably exercise typedef once and then use using everywhere else or perhaps alternate uses.

[dyniols]

@tahonermann I added typedef aliases checks in this commit 2c27f01 I am not sure if this matches what you had in mind let me know if you think it should be changed.

[tahonermann]

@tahonermann I added typedef aliases checks in this commit 2c27f01 I am not sure if this matches what you had in mind let me know if you think it should be changed.

I think that looks fine.

[dyniols]

@aelovikov-intel @lbushi25 @dklochkov-emb @tahonermann I'd appreciate an approval if everyone is aligned with the current state of the PR.