Revert of Resolve references to "this" the same way as normal variables

Revert of Resolve references to "this" the same way as normal variables (patchset #2 id:20001 of https://codereview.chromium.org/1130733003/)

Reason for revert:
[Sheriff] Breaks jetstream benchmark with errors like this:

>>> Running suite: JetStream/bigfib.cpp
>>> Stdout (#1):
undefined:93: ReferenceError: this is not defined
  this['Module'] = Module;
  ^
ReferenceError: this is not defined
    at eval (eval at __run (runner.js:13:3), <anonymous>:93:3)
    at eval (native)
    at __run (runner.js:13:3)
    at Object.runSimpleBenchmark (runner.js:44:31)
    at runner.js:97:13

Original issue's description:
> Resolve references to "this" the same way as normal variables
>
> Make the parser handle references to "this" as unresolved variables, so the
> same logic as for the rest of function parameters is used for the receiver.
> Minor additions to the code generation handle copying the receiver to the
> context, along with the rest of the function parameters.
>
> Based on work by Adrian Perez de Castro <aperez@igalia.com>;.
>
> BUG=v8:2700
> LOG=N
>
> Committed: https://crrev.com/06a792b7cc2db33ffce7244c044a9c05afbb6116
> Cr-Commit-Position: refs/heads/master@{#28263}

TBR=rossberg@chromium.org,arv@chromium.org,wingo@igalia.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=v8:2700
Committed: https://crrev.com/5cab6be83a44567a3ee5747d728a399025d38411
Cr-Commit-Position: refs/heads/master@{#28283}

[Michael Achenbach, 2015-05-07 07:20:14]

Created Revert of Resolve references to "this" the same way as normal variables

[commit-bot: I haz the power, 2015-05-07 07:20:24]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1129723003/1

[commit-bot: I haz the power, 2015-05-07 07:20:50]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-05-07 07:21:08]

Patchset 1 (id:??) landed as
https://crrev.com/5cab6be83a44567a3ee5747d728a399025d38411
Cr-Commit-Position: refs/heads/master@{#28283}

[kozy, 2015-05-25 18:55:02]

On 2015/05/07 07:21:08, I haz the power - commit-bot wrote:
> Patchset 1 (id:??) landed as
> https://crrev.com/5cab6be83a44567a3ee5747d728a399025d38411
> Cr-Commit-Position: refs/heads/master@{#28283}

It looks like it brokes evaluation this on current scope in DevTools:
https://code.google.com/p/chromium/issues/detail?id=491943
I suppose we need to revert it. Please take a look.