MIPS: ES6 computed property names

MIPS: ES6 computed property names

Port a235b1076ae4b79baae1d17a5079cb6cfc462ba3

Original commit message:
This adds support for computed property names, under the flag
--harmony-computed-property-names, for both object literals and
classes.

This is a revert of the revert, a76419f0f497db156eb1010e9b4be398951280cb with
no changes. I cannot reproduce the issue on Win8.1 or WinXP. Letting the bots
try again.

BUG=v8:3754
LOG=Y

[balazs.kilvady, 2014-12-16 17:59:52]

balazs.kilvady@imgtec.com changed reviewers:
+ akos.palfi@imgtec.com, arv@chromium.org, danno@chromium.org,
dusan.milosavljevic@imgtec.com, gergely.kis@imgtec.com, paul.lind@imgtec.com

[arv (Not doing code reviews), 2014-12-16 18:05:12]

Please wait a little bit since I'm still not sure this will stick this time.
I'll reply to this when the bots have cycled.

[balazs.kilvady, 2014-12-16 18:07:54]

On 2014/12/16 18:05:12, arv wrote:
> Please wait a little bit since I'm still not sure this will stick this time.
> I'll reply to this when the bots have cycled.

OK, thank you.

[paul.l..., 2014-12-16 18:23:45]

LGTM, once arv gives the ok to land it.

[arv (Not doing code reviews), 2014-12-16 19:38:47]

I had to revert so this patch will have to wait until I figure this out for
realz.