[AVX512] Added intrinsics for 128- and 256-bit versions of VCMPEQ{BWDQ}

Fixed lowering of this intrinsics in case when mask is v2i1 and v4i1.
Now cmp intrinsics lower in the following way:
 (i8 (int_x86_avx512_mask_pcmpeq_q_128
             (v2i64 %a), (v2i64 %b), (i8 %mask))) ->
 (i8 (bitcast
   (v8i1 (insert_subvector undef,
           (v2i1 (and (PCMPEQM %a, %b),
                      (extract_subvector
                         (v8i1 (bitcast %mask)), 0))), 0))))

llvm-svn: 218669