The function HEnvironment::SetExpressionStackAt did not update the
environment's history.  This function is used to patch the bailout
environment for count operations and global function calls.

Reorganize class HEnvironment to make it fit V8's style a bit better
and to try to add some sanity to which C++ functions are intended to
be inlined.

Remove the flag --trace-environment which merely duplicated data in
the hydrogen.cfg file except without enough context to be useful.

BUG=1004

Review URL: http://codereview.chromium.org/5992011

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6137 ce2b1a6d-e550-0410-aec6-3dcde31c8c00