Inline immutable property loads

When a non-configurable, non-writable field is
read from a constant holder, the load is
eliminated and replaced with the direct value
of the field

BUG=
R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/232853002

Patch from Petka Antonov <p.antonov@partner.samsung.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@20690 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Merge remote-tracking branch 'upstream/master'