Removed bogus check for TOP register in deoptimizer. (Chromium issue 176943)

Made the Isolate parameter mandatory for internal HandleScopes. (issue 2487)

Fixed f.apply() optimization when declared arguments are mutated. (issue 2539)

Performance and stability improvements on all platforms.

git-svn-id: http://v8.googlecode.com/svn/trunk@13692 ce2b1a6d-e550-0410-aec6-3dcde31c8c00