[SYCL] Allocate sycl::handler on the stack when possible

[Alexandr-Konovalov]

There are two set of changes:

1. On hot path handler_impl is allocated on stack.
2. handler keeps reference to queue shared_ptr, not shared_ptr.

[vinser52]

@againull Could you please review?

[bader]

Fix grammar in the PR title:
"[SYCL] Allocate sycl::handler in stack when possible" ->
"[SYCL] Allocate sycl::handler on the stack when possible"

[Alexandr-Konovalov]

@intel/llvm-reviewers-runtime , Colleagues, I see ThreadSanitizer/check_usm.cpp failed for other PRs as well, and there are 2 approvals. What are possible next steps?

[vinser52]

@intel/llvm-reviewers-runtime , Colleagues, I see ThreadSanitizer/check_usm.cpp failed for other PRs as well, and there are 2 approvals. What are possible next steps?

I think the issue is unrelated to this PR, see #17486

[aelovikov-intel]

Why Queue.get() here instead of nullptr? handler_impl ctor expects secondary queue here, not primary one.

[Alexandr-Konovalov]

Thank you, opened PR #18752 with the fix.