Version 3.26.21 (based on bleeding_edge revision r20893)

Context-allocate all parameters in generators (issue 3280).

Simplify v8/Isolate teardown (Chromium issue 359977).

Performance and stability improvements on all platforms.

git-svn-id: https://v8.googlecode.com/svn/trunk@20895 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Merge remote-tracking branch 'upstream/trunk' into trunk