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

Review URL: https://codereview.chromium.org/109033003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18420 ce2b1a6d-e550-0410-aec6-3dcde31c8c00