Revert of Debugger: use FrameInspector in ScopeIterator to find context.

Revert of Debugger: use FrameInspector in ScopeIterator to find context. (patchset #3 id:40001 of https://codereview.chromium.org/1239033002/)

Reason for revert:
breaks roll: http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_rel_ng/builds/87292/steps/browser_tests%20%28with%20patch%29/logs/DevToolsSanityTest.TestPauseWhenScriptIsRunning

Original issue's description:
> Debugger: use FrameInspector in ScopeIterator to find context.
>
> In optimized code, it's not guaranteed that the current context
> is stored in its frame slot.
>
> R=bmeurer@chromium.org
> BUG=v8:4309
> LOG=N
>
> Committed: https://crrev.com/3a0ee39cbde6a9778cfc4e2a6a0a8ff68933ff38
> Cr-Commit-Position: refs/heads/master@{#29697}

TBR=bmeurer@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:4309
Committed: https://crrev.com/c062b28aebdf881674b074f0727dfbf00b936db8
Cr-Commit-Position: refs/heads/master@{#29722}

[Yang, 2015-07-17 09:53:28]

Created Revert of Debugger: use FrameInspector in ScopeIterator to find context.

[commit-bot: I haz the power, 2015-07-17 09:53:35]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1243553002/1

[commit-bot: I haz the power, 2015-07-17 09:53:46]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-17 09:54:01]

Patchset 1 (id:??) landed as
https://crrev.com/c062b28aebdf881674b074f0727dfbf00b936db8
Cr-Commit-Position: refs/heads/master@{#29722}

[Michael Achenbach, 2015-07-17 09:55:45]

machenbach@chromium.org changed reviewers:
+ machenbach@chromium.org

[Michael Achenbach, 2015-07-17 09:55:45]

lgtm