This change applies x86avxgen output.
https://go-review.googlesource.com/c/arch/+/66972
As an effect, many new AVX instructions are now available.

One of the side-effects of this patch is
sorted AXXX (A-enum) constants.

Some AVX1/2 instructions still not added due to:
1. x86.csv V0.2 does not list them;
2. partially because of (1), test suite does not contain tests for
   these instructions.

Change-Id: I90430d773974ca5c995d6950d90e2c62ec88ef47
Reviewed-on: https://go-review.googlesource.com/75490
Run-TryBot: Iskander Sharipov <iskander.sharipov@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>