[parser] reject AssignmentElements with non-ASSIGN initializer ops

[parser] reject AssignmentElements with non-ASSIGN initializer ops

When parsing a pattern element with an assignment operator that is not
Token::ASSIGN, record a pattern error to indicate the invalid assignment target.

BUG=v8:811, v8:4666
LOG=N
R=adamk@chromium.org, rossberg@chromium.org, littledan@chromium.org

Committed: https://crrev.com/d19e3a21d6f2785280d84d70a7c7de89e391a949
Cr-Commit-Position: refs/heads/master@{#33279}

[caitp (gmail), 2016-01-14 02:30:22]

quick fix for the fuzzer error --- I'll do a followup to unify paths with the
similar error for binding patterns, and improve the binding pattern message a
bit --- but that can wait

[adamk, 2016-01-14 02:32:46]

lgtm

[caitp (gmail), 2016-01-14 02:34:20]

The CQ bit was checked by caitpotter88@gmail.com

[commit-bot: I haz the power, 2016-01-14 02:34:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1583863003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1583863003/1

[commit-bot: I haz the power, 2016-01-14 03:08:46]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-01-14 03:09:23]

Description was changed from

==========
[parser] reject AssignmentElements with non-ASSIGN initializer ops

When parsing a pattern element with an assignment operator that is not
Token::ASSIGN, record a pattern error to indicate the invalid assignment target.

BUG=v8:811, v8:4666
LOG=N
R=adamk@chromium.org, rossberg@chromium.org, littledan@chromium.org
==========

to

==========
[parser] reject AssignmentElements with non-ASSIGN initializer ops

When parsing a pattern element with an assignment operator that is not
Token::ASSIGN, record a pattern error to indicate the invalid assignment target.

BUG=v8:811, v8:4666
LOG=N
R=adamk@chromium.org, rossberg@chromium.org, littledan@chromium.org

Committed: https://crrev.com/d19e3a21d6f2785280d84d70a7c7de89e391a949
Cr-Commit-Position: refs/heads/master@{#33279}
==========

[commit-bot: I haz the power, 2016-01-14 03:09:24]

Patchset 1 (id:??) landed as
https://crrev.com/d19e3a21d6f2785280d84d70a7c7de89e391a949
Cr-Commit-Position: refs/heads/master@{#33279}