Currently only simple setter calls are handled (i.e. no calls in count
operations or compound assignments), and deoptimization in the setter is not
handled at all. Because of the latter, we temporarily hide this feature behind
the --inline-accessors flag, just like inlining getters.

We now use an enum everywhere we depend on the handling of a return value,
passing around several boolean would be more confusing.

Made VisitReturnStatement and the final parts of TryInline more similar, so
matching them visually is a bit easier now.

Simplified the signature of AddLeaveInlined, the target of the HGoto can simply
be retrieved from the function state.

Review URL: https://chromiumcodereview.appspot.com/10836133

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12286 ce2b1a6d-e550-0410-aec6-3dcde31c8c00