Support VZEROUPPER, VMOVNTDQ, VMOVDQU, VMOVDQA.
Use MOVHD* for names, where HD stands for HexaDeca (16).

Change-Id: I9b1ea52e7ef0714a3d2aeb31ec1823fe509a047e
Reviewed-on: https://go-review.googlesource.com/14127
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>