[SYCL][NFC] Prepare for -Wconversion [1/N]

[AlexeySachkov]

-Wconversion is required per our SDL processes and it will be enabled in #19306.

Updated all literal arguments passed to UR APIs, because corresponding functions expect an unsigned integer.

[AlexeySachkov]

I see sporadic failures on Windows, but I don't think that they are anyhow related to the patch: the very first version (before applying clang-format) passed all tests.

What I see now is

Test d:\github\_work\llvm\llvm\build-e2e\workgroupmemory\output\basic_usage.cpp.tmp.out hung!

And on restart:

FAIL: SYCL :: Reduction/reduction_big_data.cpp (740 of 2450)
******************** TEST 'SYCL :: Reduction/reduction_big_data.cpp' FAILED ********************
Exit Code: 3221225477

Command Output (stdout):
--
# RUN: at line 2
env ONEAPI_DEVICE_SELECTOR=level_zero:gpu  D:\github\_work\llvm\llvm\build-e2e\Reduction\Output\reduction_big_data.cpp.tmp.out
# executed command: env ONEAPI_DEVICE_SELECTOR=level_zero:gpu 'D:\github\_work\llvm\llvm\build-e2e\Reduction\Output\reduction_big_data.cpp.tmp.out'
# .---command stdout------------
# | Device: Intel(R) Arc(TM) B580 Graphics, MaxWGSize: 1024, LocalMemSize: 131072, Driver: 1.6.33511
# | Start, T=float, BOp=struct sycl::_V1::maximum<void>, Range={{1049600}, {1024}}. PASSED
# `-----------------------------
# error: command failed with exit status: 0xc0000005

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