Revert of document.querySelector[All]() should check selector context

Revert of document.querySelector[All]() should check selector context (patchset #6 id:100001 of https://codereview.chromium.org/1245933002/ )

Reason for revert:
This seems to have caused a significant perf
regression.  Reverting.

BUG=526742
Original issue's description:
> document.querySelector[All]() should check selector context
> 
> Blink failed to check whether the left-most matched selector ends up
> in Document TreeScope.
> The check was only enabled for querySelector*() is called on
> a regular element, not on document.
> 
> This issue can be exposed by passing "::shadow" or "/deep/"
> which pierces shadow boundary and the selector can
> incorrectly match inside shadow.
> 
> BUG=511486
> TEST=fast/dom/shadow/querySelector-with-shadow-all-and-shadow-deep.html
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=201461

TBR=esprehn@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=511486
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=201514

[kochi, 2015-09-01 02:20:08]

Created Revert of document.querySelector[All]() should check selector context

[commit-bot: I haz the power, 2015-09-01 02:20:21]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1329523002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1329523002/1

[commit-bot: I haz the power, 2015-09-01 02:20:48]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=201514