Make control reducer revisit newly introduced merges.

Make control reducer revisit newly introduced merges.

TEST=mjsunit/compiler/regress-445876
BUG=chromium:445876
LOG=N

Committed: https://crrev.com/a9716d98401d65273f7adfcca906dbd088776a01
Cr-Commit-Position: refs/heads/master@{#25959}

[Jarin, 2015-01-05 12:30:45]

jarin@chromium.org changed reviewers:
+ bmeurer@chromium.org

[Jarin, 2015-01-05 12:31:20]

Could you take a look, please?

[Benedikt Meurer, 2015-01-05 12:32:06]

The CQ bit was checked by bmeurer@chromium.org

[Benedikt Meurer, 2015-01-05 12:32:07]

LGTM

[commit-bot: I haz the power, 2015-01-05 12:32:14]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/830293003/1

[titzer, 2015-01-05 12:35:24]

titzer@chromium.org changed reviewers:
+ titzer@chromium.org

[titzer, 2015-01-05 12:35:24]

lgtm

[commit-bot: I haz the power, 2015-01-05 13:09:55]

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

[commit-bot: I haz the power, 2015-01-05 13:09:56]

Try jobs failed on following builders:
  v8_linux64_asan_rel on tryserver.v8
(http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_asan_rel/builds/565)

[Jarin, 2015-01-05 16:08:15]

The CQ bit was checked by jarin@chromium.org

[commit-bot: I haz the power, 2015-01-05 16:08:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/830293003/40001

[commit-bot: I haz the power, 2015-01-05 16:35:20]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2015-01-05 16:35:51]

Patchset 3 (id:??) landed as
https://crrev.com/a9716d98401d65273f7adfcca906dbd088776a01
Cr-Commit-Position: refs/heads/master@{#25959}