Make generator constructors configurable

Make generator constructors configurable

R=mstarzinger@chromium.org
BUG=v8:3902
LOG=Y

Committed: https://crrev.com/4c082b570da7f53f8f650764b513705f08c62093
Cr-Commit-Position: refs/heads/master@{#26744}

[Michael Starzinger, 2015-02-19 10:19:41]

LGTM. Please prefix the BUG-line in the description with "v8:" so that it's
properly linked.

[rossberg, 2015-02-19 10:51:52]

The CQ bit was checked by rossberg@chromium.org

[commit-bot: I haz the power, 2015-02-19 10:52:20]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/939953002/1

[commit-bot: I haz the power, 2015-02-19 10:55:31]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-02-19 10:55:32]

Try jobs failed on following builders:
  v8_presubmit on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_presubmit/builds/680)

[rossberg, 2015-02-19 11:26:58]

The CQ bit was checked by rossberg@chromium.org

[commit-bot: I haz the power, 2015-02-19 11:27:50]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/939953002/1

[commit-bot: I haz the power, 2015-02-19 11:30:29]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-19 11:30:39]

Patchset 1 (id:??) landed as
https://crrev.com/4c082b570da7f53f8f650764b513705f08c62093
Cr-Commit-Position: refs/heads/master@{#26744}