Symbols for type cells. We can make more efficient code to check against type cells in the future if we use symbols, guaranteed not to conflict with user code. Currently, the "symbols" are the hole and undefined. Undefined may come in from the outside.

BUG=
R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/181283003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@19706 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Update .gitignore to new test262 package name.

R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/188923003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@19707 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
A64: Minor improvement in FullCodeGenerator::VisitObjectLiteral.

This patch avoid to push some values on the stack when it's not needed.

R=ulan@chromium.org

Review URL: https://codereview.chromium.org/183193005

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@19708 ce2b1a6d-e550-0410-aec6-3dcde31c8c00