Revert 216795 "Adding check for OS support to AVX"

Revert 216795 "Adding check for OS support to AVX"

Lots of tree breakages on Windows bots.

> Adding check for OS support to AVX
> 
> AVX support requires OS level support, this patch adds the relevant
> checks to ensure AVX is truly supported on a given cpu.
> 
> It also fixes a missing initializer for has_avx_.
> 
> This is a takeover of https://codereview.chromium.org/12511002/ from
> whunt@ who no longer works on the Chrome team.
> 
> BUG=171824
> TEST=none
> TBR=brettw,apatrick_chromium,whunt
> 
> Review URL: https://chromiumcodereview.appspot.com/22354004

TBR=dalecurtis@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=216807

[Lei Zhang, 2013-08-10 05:23:58]

Committed patchset #1 manually as r216807.

[DaleCurtis, 2013-08-12 17:35:13]

When you say lots, can you provide links?  I can only see one failure which
might be related on the Win TSAN bot:

http://build.chromium.org/p/chromium.memory.fyi/builders/Windows%20Tests%20%2...

[Lei Zhang, 2013-08-12 17:40:26]

I think it was mainly XP bots. Go through the Windows bots, and select Show ->
200. Here's one example:

http://build.chromium.org/p/chromium.win/builders/XP%20Tests%20%282%29/builds...