[WIP][SYCL][ESIMD] Replace mask_type_t with simd_mask to represent Gen predicates.

[kbobrovs]

This patch introduces simd_mask class which represents a Gen simd operation mask.
Aims to have similar interface to std::experimantal::simd_mask:
(https://github.com/llvm/llvm-project/blob/main/libcxx/include/experimental/simd)
Compared to std::experimantal::simd_mask, this implementation

• does not provide the following members/features:
  • abi_type (not needed for ESIMD)
  • simd_type (not needed for ESIMD)
  • reference (TODO)
  • implicit type conversion constructor (not needed for ESIMD)
  • reference operator (TODO)
  • flags in memory load/store operations (TODO)
  • reduction functions (TODO):
    any_of, all_of, some_of, none_of, popcount, find_first_set, find_last_set
• additionally provides some extra features, like
  • broadcast constructor for any integer type
  • implicit conversion from the simd class
  • constructor from fixed-size array
  • ... few more

TODO (WIP): select and iupdate operations

This patch addresses this review comment:
// TODO @rolandschulz on May 21
// {quote}
// - The mask should also be a wrapper around the clang - vector type rather
// than the clang - vector type itself.
// - The internal storage should be implementation defined.uint16_t is a bad
// choice for some HW.Nor is it how clang - vector types works(using the same
// size int as the corresponding vector type used for comparison(e.g. long for
// double and int for float)).

E2E test: intel/llvm-test-suite#286

Signed-off-by: kbobrovs [email protected]

[kychendev]

• The patch doesn’t cover esimd pack_mask/unpack_mask yet, which are useful mask operations. Please update it as well.
• There is no support for mask select operation. This will be inconvenient for ESIMD programmers.
• Please make similar changes to REL operators defined in esimd_view.hpp to handle masks generated from comparison operation of simd_view objects.

[kbobrovs]

Replaced with #4230