Harden internal uses of .chain

R=yangguo@chromium.org
BUG=

Review URL: https://codereview.chromium.org/212553009

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20309 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Revert "Fix property enum cache creation to include only own properties"

This reverts commit 4cf47a20b4846cf050ea4844433e9c57654da34e.

BUG=

Review URL: https://codereview.chromium.org/214893002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20310 ce2b1a6d-e550-0410-aec6-3dcde31c8c00