Add code kind check before preparing for OSR. (issue 1900, 115073)

Pass zone explicitly to zone-allocation on x64 and ARM. (issue 1802)

Port string construct stub to x64. (issue 849)

Performance and stability improvements on all platforms.

git-svn-id: http://v8.googlecode.com/svn/trunk@10875 ce2b1a6d-e550-0410-aec6-3dcde31c8c00