Revert "Treat ExecutableAccessorInfo as regular data properties."

Temporarily revert since blink has some properties like this on the
prototype chain where it expects accessorpair-behavior (e.g.,
window.onload).

TBR=dslomov@chromium.org
BUG=

Review URL: https://codereview.chromium.org/378583002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22251 ce2b1a6d-e550-0410-aec6-3dcde31c8c00