Revert of Lazily register prototype users

Revert of Lazily register prototype users (patchset #2 id:20001 of https://codereview.chromium.org/1104813004/)

Reason for revert:
Suspected of causing GC stress failures.

Original issue's description:
> Lazily register prototype users
>
> when handing out validity cells to handles; because invalidating said cells is the only time we'll need the user registrations.
> Along the way, fix a corner case in WeakFixedArray, which can now be empty after the recently introduced compaction support.
>
> Committed: https://crrev.com/a4bb7643c076b014816431a9b85af3e2edf828e7
> Cr-Commit-Position: refs/heads/master@{#28047}

TBR=yangguo@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Committed: https://crrev.com/968715c653b6337252a05a0224a7a93fab3b0866
Cr-Commit-Position: refs/heads/master@{#28049}

[Jakob Kummerow, 2015-04-24 14:09:48]

Created Revert of Lazily register prototype users

[commit-bot: I haz the power, 2015-04-24 14:10:02]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1108583002/1

[commit-bot: I haz the power, 2015-04-24 14:10:15]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-24 14:10:27]

Patchset 1 (id:??) landed as
https://crrev.com/968715c653b6337252a05a0224a7a93fab3b0866
Cr-Commit-Position: refs/heads/master@{#28049}