Fix a race between concurrent recompilation and OSR.

Fix a race between concurrent recompilation and OSR.

If concurrent recompilation finishes before OSR, then OSR replaces
the old optimized code without evicting it from the optimized code map.

New functions can get the old optimized code from the optimized code map,
but the old code could be already deoptimized.

BUG=330046
TEST=test/mjsunit/regress-330046.js
LOG=Y
R=yangguo@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=18420

[ulan, 2013-12-24 11:42:26]

Please take a look.

[Yang, 2013-12-24 12:45:46]

On 2013/12/24 11:42:26, ulan wrote:
> Please take a look.

LGTM.

[ulan, 2013-12-27 09:23:03]

Committed patchset #1 manually as r18420 (presubmit successful).