Remove special-casing of EAGER and SOFT deoptimization calling conventions, allowing calling address to always be available to deoptimization entries.
BUG=

Review URL: https://codereview.chromium.org/18356008

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15640 ce2b1a6d-e550-0410-aec6-3dcde31c8c00