Defer CONST_LEGACY redeclaration errors until runtime in harmony mode

Defer CONST_LEGACY redeclaration errors until runtime in harmony mode

This fixes a corner-case in redeclaration handling, where the ES2015
early error case got mixed up with legacy const handling in the parser.

Redeclaration using ES2015 'let' and 'const' should be early errors,
but legacy 'const' redeclaration has historically been a runtime error,
and should stay that way until legacy 'const' is gone.

The fix here is uglier than it might be due to
https://code.google.com/p/v8/issues/detail?id=4577, which keeps us
from simplifying the mess of if/else-if in the current code.

BUG=v8:4576
LOG=n

Committed: https://crrev.com/6c6dd449c3e17f30905a34242ebe2f0c42a24958
Cr-Commit-Position: refs/heads/master@{#32429}

[adamk, 2015-12-01 00:49:37]

adamk@chromium.org changed reviewers:
+ littledan@chromium.org

[Dan Ehrenberg, 2015-12-01 00:55:15]

lgtm

[adamk, 2015-12-01 01:02:27]

The CQ bit was checked by adamk@chromium.org

[commit-bot: I haz the power, 2015-12-01 01:02:31]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1485943002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1485943002/1

[commit-bot: I haz the power, 2015-12-01 01:18:57]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-12-01 01:20:05]

Description was changed from

==========
Defer CONST_LEGACY redeclaration errors until runtime in harmony mode

This fixes a corner-case in redeclaration handling, where the ES2015
early error case got mixed up with legacy const handling in the parser.

Redeclaration using ES2015 'let' and 'const' should be early errors,
but legacy 'const' redeclaration has historically been a runtime error,
and should stay that way until legacy 'const' is gone.

The fix here is uglier than it might be due to
https://code.google.com/p/v8/issues/detail?id=4577, which keeps us
from simplifying the mess of if/else-if in the current code.

BUG=v8:4576
LOG=n
==========

to

==========
Defer CONST_LEGACY redeclaration errors until runtime in harmony mode

This fixes a corner-case in redeclaration handling, where the ES2015
early error case got mixed up with legacy const handling in the parser.

Redeclaration using ES2015 'let' and 'const' should be early errors,
but legacy 'const' redeclaration has historically been a runtime error,
and should stay that way until legacy 'const' is gone.

The fix here is uglier than it might be due to
https://code.google.com/p/v8/issues/detail?id=4577, which keeps us
from simplifying the mess of if/else-if in the current code.

BUG=v8:4576
LOG=n

Committed: https://crrev.com/6c6dd449c3e17f30905a34242ebe2f0c42a24958
Cr-Commit-Position: refs/heads/master@{#32429}
==========

[commit-bot: I haz the power, 2015-12-01 01:20:06]

Patchset 1 (id:??) landed as
https://crrev.com/6c6dd449c3e17f30905a34242ebe2f0c42a24958
Cr-Commit-Position: refs/heads/master@{#32429}