[Clang][Test] Fix sycl-cuda-host-device-functions test
Update CHECK patterns to expect spir_func calling convention in SPIRV
device mode outputs. The test regex was incomplete and didn't account
for the spir_func calling convention that appears in function
declarations/definitions for SPIRV targets.
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
