Add support for raw_kernel_arg extension

[sommerlukas]

Add support for the DPC++ SYCL extension raw_kernel_arg that allows to pass a binary blob as kernel arguments.

This is for example useful if the kernel uses a struct as kernel parameter, but is loaded from SPIR-V and the argument type is unknown for set_arg.

The implementation follows #1984.

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[coveralls]

coverage: 86.354% (-0.06%) from 86.41%
when pulling 5fb74e6 on sommerlukas:raw-kernel-arg
into 3e74087 on IntelPython:master.

[ndgrigorian]

@sommerlukas
Master now has a fix for nightly build, so please merge or rebase on master so the tests run on nightly compiler

[sommerlukas]

Thanks for the feedback @ndgrigorian @AlexanderKalistratov!

After taking a look at how the opaque pointers for other std::vector work, I've changed the approach: I've removed RawKernelArgDataTy entirely, so that the opaque pointer (DPCTLSyclRawKernelArgRef) now directly points to std::vector<unsigned char>. That way, we can avoid defining a struct with std::vector in the header, so the offending includes of <vector> and <cstring> are now removed.

[sommerlukas]

@ndgrigorian @AlexanderKalistratov Friendly ping for reviews. CI is looking quite good now, I can unfortunately not see the logs for the single failing Jenkins job.

[AlexanderKalistratov]

@sommerlukas PR looks great for me, thank you!
I'm not code owner, so we need to wait @ndgrigorian review as well

[ndgrigorian]

@ndgrigorian @AlexanderKalistratov Friendly ping for reviews. CI is looking quite good now, I can unfortunately not see the logs for the single failing Jenkins job.

Sorry, forgot to put my final review on this.

Jenkins job is unrelated. I'll give it a last look over but I think it's ready to go in.

[ndgrigorian]

LGTM!