Change vector equality to use pmovmskb

Change vector equality to use pmovmskb

This change replaces the rather long shuffle based compare sequence with
pmovmskb which is available in SSE2 and AVX2. The following code is now
generated:

C4E16D76D1           vpcmpeqd ymm2, ymm1
C4E17DD7C2           vpmovmskbeax, ymm2
83F8FF               cmp      eax, -1
0F94C0               sete     al
0FB6C0               movzx    rax, al