Fix maybe_string_add for adds that have no type feedback where --always-opt is on.

Fix maybe_string_add for adds that have no type feedback where --always-opt is on.

R=mstarzinger@chromium.org
BUG=

Committed: https://crrev.com/a511c78999f508da1c5e447783c238916b2ca0a2
Cr-Commit-Position: refs/heads/master@{#27667}

[Michael Starzinger, 2015-04-08 11:57:30]

LGTM. Thanks!

[titzer, 2015-04-08 11:58:20]

The CQ bit was checked by titzer@chromium.org

[commit-bot: I haz the power, 2015-04-08 11:58:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1071473003/20001

[titzer, 2015-04-08 11:59:15]

The CQ bit was unchecked by titzer@chromium.org

[titzer, 2015-04-08 12:41:27]

The CQ bit was checked by titzer@chromium.org

[titzer, 2015-04-08 12:41:27]

The patchset sent to the CQ was uploaded after l-g-t-m from
mstarzinger@chromium.org
Link to the patchset: https://codereview.chromium.org/1071473003/#ps40001
(title: " ")

[commit-bot: I haz the power, 2015-04-08 12:41:36]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1071473003/40001

[commit-bot: I haz the power, 2015-04-08 12:42:59]

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

[commit-bot: I haz the power, 2015-04-08 12:43:00]

Try jobs failed on following builders:
  v8_linux_arm64_rel on tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_arm64_rel/builds/4538)

[titzer, 2015-04-08 12:50:18]

The CQ bit was checked by titzer@chromium.org

[titzer, 2015-04-08 12:50:19]

The patchset sent to the CQ was uploaded after l-g-t-m from
mstarzinger@chromium.org
Link to the patchset: https://codereview.chromium.org/1071473003/#ps60001
(title: "Merge status file.")

[commit-bot: I haz the power, 2015-04-08 12:50:35]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1071473003/60001

[commit-bot: I haz the power, 2015-04-08 13:14:30]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2015-04-08 13:14:43]

Patchset 4 (id:??) landed as
https://crrev.com/a511c78999f508da1c5e447783c238916b2ca0a2
Cr-Commit-Position: refs/heads/master@{#27667}