Add a lexical scope for the body of a with statement

Add a lexical scope for the body of a with statement

For an edge case like the following in sloppy mode
  with ({}) function f() {}
a lexical scope needs to be created around the body in order
to hold the function declaration, so it can be hoisted according
to a loose interpretation of Annex B 3.3 (loose because ES2015
does not permit a function declaration as the body of a with
statement). This patch adds that scope.

BUG=chromium:542100
LOG=N
R=adamk

Committed: https://crrev.com/ab3110e87551cfd553cda87e13c6a6c008af87e7
Cr-Commit-Position: refs/heads/master@{#31269}

[Dan Ehrenberg, 2015-10-14 15:12:24]

The CQ bit was checked by littledan@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-10-14 15:12:31]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1404803002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1404803002/1

[commit-bot: I haz the power, 2015-10-14 15:34:01]

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

[commit-bot: I haz the power, 2015-10-14 15:34:02]

Dry run: This issue passed the CQ dry run.

[adamk, 2015-10-14 15:43:37]

lgtm, sad we need all this code to support this one case

[Dan Ehrenberg, 2015-10-14 15:44:26]

The CQ bit was checked by littledan@chromium.org

[commit-bot: I haz the power, 2015-10-14 15:44:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1404803002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1404803002/1

[Dan Ehrenberg, 2015-10-14 15:44:45]

Yeah, but apparently function declarations directly in with scopes is supported
across browsers (at least in Firefox)

[commit-bot: I haz the power, 2015-10-14 17:37:21]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-14 17:37:32]

Patchset 1 (id:??) landed as
https://crrev.com/ab3110e87551cfd553cda87e13c6a6c008af87e7
Cr-Commit-Position: refs/heads/master@{#31269}