Remove obsolete Code::optimizable flag.

Remove obsolete Code::optimizable flag.

This flag mostly duplicates SharedFunctionInfo::optimization_disabled
and is only queried in places where the original is available. Remove
the brittle and error-prone duplication.

R=bmeurer@chromium.org

Committed: https://crrev.com/794aa072830ac53e9267775956b9bf864e4e0779
Cr-Commit-Position: refs/heads/master@{#28520}

[titzer, 2015-05-20 14:13:10]

On 2015/05/20 13:39:55, Michael Starzinger wrote:

LGTM

[Michael Starzinger, 2015-05-20 14:42:55]

The CQ bit was checked by mstarzinger@chromium.org

[commit-bot: I haz the power, 2015-05-20 14:43:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1148043002/1

[commit-bot: I haz the power, 2015-05-20 14:45:07]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-05-20 14:45:23]

Patchset 1 (id:??) landed as
https://crrev.com/794aa072830ac53e9267775956b9bf864e4e0779
Cr-Commit-Position: refs/heads/master@{#28520}