[es6] Make sure temporaries are not allocated in block scope

[es6] Make sure temporaries are not allocated in block scope

While at it, remove the notion of INTERNAL variables.

@caitp: Took some parts from your CL, since I was blocked on the temp scope bug.

R=mstarzinger@chromium.org
BUG=512574
LOG=N

Committed: https://crrev.com/9ab8bfba7fe237709d0ba3dc0c6acbf0653beab7
Cr-Commit-Position: refs/heads/master@{#29812}

[Michael Starzinger, 2015-07-23 13:25:01]

LGTM.

[rossberg, 2015-07-23 13:25:31]

The CQ bit was checked by rossberg@chromium.org

[commit-bot: I haz the power, 2015-07-23 13:25:47]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1250513004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1250513004/1

[commit-bot: I haz the power, 2015-07-23 13:29:03]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-07-23 13:29:04]

Try jobs failed on following builders:
  v8_presubmit on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_presubmit/builds/4398)

[rossberg, 2015-07-23 13:31:57]

The CQ bit was checked by rossberg@chromium.org

[commit-bot: I haz the power, 2015-07-23 13:32:13]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1250513004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1250513004/1

[commit-bot: I haz the power, 2015-07-23 13:51:32]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-23 13:51:42]

Patchset 1 (id:??) landed as
https://crrev.com/9ab8bfba7fe237709d0ba3dc0c6acbf0653beab7
Cr-Commit-Position: refs/heads/master@{#29812}