Allow users of the V8 API to distinguish between unset and undefined HiddenValues

BUG=v8:2746
R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/17781002

Patch from Adam Klein <adamk@chromium.org>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15329 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Remove useless ZoneScopes from Parser.

R=danno@chromium.org
BUG=

Review URL: https://codereview.chromium.org/17817003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15330 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Change PC for OSR entries to point to something more sensible (i.e. the first UnknownOsrValue), removing the need to record spilled OSR values and the need for duplicate deopt entries.

Review URL: https://codereview.chromium.org/16381006

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15331 ce2b1a6d-e550-0410-aec6-3dcde31c8c00