Test plan for parallel_for simplifications

The parallel_for overload without an offset can be called with either a number or a braced-init-list with 1-3 elements. It’s described in https://registry.khronos.org/SYCL/specs/sycl-2020/html/sycl-2020.html#_parallel_for_invoke

1. Testing scope

1.1. Device coverage

All of the tests described below are performed only on the default device that is selected on the CTS command line

2. Tests

For following kernel invocations:

parallel_for(N, some_kernel) with array size is N
parallel_for({N}, some_kernel) with array size is N
parallel_for({N1, N2}, some_kernel) with array size is N1 * N2
parallel_for({N1, N2, N3}, some_kernel) with array size is N1 * N2 * N3

With N, N1 = 2, N2 = 3, N3 = 5.

Create an array of corresponding size and buffer for access to it.
Invoke some_kernel that takes item argument and fills buffer via accessor with linear_id of the item.
Check that all elements of array is equal to its index.