Unify (Pre)Parser::ParseObjectLiteral and add tests.

Unify (Pre)Parser::ParseObjectLiteral and add tests.

Notes:
- The regexp in the ParseObjectLiteralComment was wrong, made it less wrong (
it's still wrong since trailing commas are not required / allowed).
- Change in logic: In case we have "get somekeyword() { }", the "somekeyword"
was not logged as a symbol by PreParser and not expected in the preparser data
by Parser. This is unnecessary complication; in other contexts where keywords
are allowed as identifiers, they are logged as symbols (see
ParseIdentifierName).

BUG=v8:3126
LOG=N
R=ulan@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=19750

[marja, 2014-02-20 15:36:29]

ulan, ptal

[ulan, 2014-02-20 15:53:21]

lgtm

[marja, 2014-03-10 11:42:44]

Committed patchset #1 manually as r19750 (presubmit successful).