Prior to this patch kernel generation copied kernel argument types
exactly as they're written in function's signature of the function
attributed with [[clang::sycl_kernel_entry_point]] attribute. This
caused generation of kernels that have reference kernel argument instead
of byval kernel argument.
SYCL 2020 doesn't allow reference kernel arguments and it doesn't seem
to work with the backends.
Arguments to [[clang::sycl_kernel_entry_point]]-attributed function can
be big, so we preserve references during host code generation to avoid
performance issues in SYCL Runtime library implementation because the
same function will be used for actual kernel argument setting via
sycl_kernel_launch interface.
Note that we still need to diagnose references in user's kernel
arguments since they are explicitly not allowed by SYCL 2020 spec and
this task is in TODO list. This patch simply removes references from
types written in SYCL Runtime library.
Assisted-by: claude in test writing.
2857f3bb6a