Revert of Make allow_subannotations more robust.

Revert of Make allow_subannotations more robust. (patchset #7 id:120001 of https://codereview.chromium.org/1001183002/)

Reason for revert:
Maybe it broke extract_build

Original issue's description:
> Make allow_subannotations more robust.
> 
> This patch makes the recipe engine parse and re-emit subannotations when allow_subannotations is True.  This means that any of the subannotator's steps which are duplicates of other steps executed will be disambiguated.  When an allow_subannotations step is actually emits annotations, an (end) step is emitted after it is done to have something to hang metadata on (it also conveniently communicates when we re-enter recipes).
> 
> BUG=466409
> 
> Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=294727

TBR=iannucci@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=466409
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=294729

[luqui, 2015-04-08 20:57:22]

Created Revert of Make allow_subannotations more robust.

[commit-bot: I haz the power, 2015-04-08 20:57:41]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1071733003/1

[commit-bot: I haz the power, 2015-04-08 20:57:52]

Committed patchset #1 (id:1) as
http://src.chromium.org/viewvc/chrome?view=rev&revision=294729

[luqui, 2015-04-08 22:25:10]

Reland here https://codereview.chromium.org/1076643002/