ITT / XPTI support

[TApplencourt]

We should be able to use those callbacks

ITT

https://github.com/intel/pti-gpu/blob/master/tools/unitrace/src/itt/itt_collector.h

(info on the API: https://github.com/intel/ittapi/blob/master/include/ittnotify.h)

XPTI

https://github.com/intel/llvm/blob/sycl/xptifw/doc/XPTI_Framework.md
https://github.com/intel/pti-gpu/blob/master/tools/unitrace/src/xpti/xpti_collector.h
https://github.com/intel/llvm/blob/sycl/xptifw/samples/basic_collector/basic_collector.cpp

[TApplencourt]

Itt plan:

• Test Unitrace with different programming models, and see which ITT tracepoint they have
• Understand better all the ITT tracepoints (__itt_stack_callee_enter)
• Create a standalone ITT tool that prints begin / end event tracer_itt.c
• Generate Thapi Tracepoint (create .yaml)
• Modify ITT: To use THAPI-Tracepoint tracer_itt.c
• Create new metababel ITT interval (copy btx_omp)
• Profit

[nscottnichols]

Partially complete with #423

[nscottnichols]

The ITT backend is complete with #423, #445, and #452. Are you still interested in adding XPTI?