Expose Map/Set methods through the API

Expose Map/Set methods through the API

Map: get, set, has, delete, clear
Set: add, has, delete, clear

All except clear are implemented as calls into collection.js.

Note that some of these shadow methods of v8::Object. It's unclear
how confusing that's going to be: on the one hand, it seems likely
that most operations you would want to do on a Map or Set are these.
On the other, generic code could get confused if it somehow gets
ahold of a variable that happens to be C++-typed as a v8::Map or v8::Set.

BUG=v8:3340
LOG=y

Committed: https://crrev.com/df472240285a93f25edac20100db2240fae5c7c6
Cr-Commit-Position: refs/heads/master@{#29237}

[adamk, 2015-06-23 00:41:10]

adamk@chromium.org changed reviewers:
+ arv@chromium.org, jochen@chromium.org

[jochen (gone - plz use gerrit), 2015-06-23 14:57:06]

api lgtm

[arv (Not doing code reviews), 2015-06-23 15:01:14]

LGTM

[adamk, 2015-06-23 15:12:26]

The CQ bit was checked by adamk@chromium.org

[commit-bot: I haz the power, 2015-06-23 15:12:40]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1204623002/1

[commit-bot: I haz the power, 2015-06-23 15:14:13]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-06-23 15:14:30]

Patchset 1 (id:??) landed as
https://crrev.com/df472240285a93f25edac20100db2240fae5c7c6
Cr-Commit-Position: refs/heads/master@{#29237}