Modify PreProcessOsrEntry to work with OSR entries that have non-empty expression stack.

Modify graph builder to take for-in state from environment instead of directly referencing emitted instructions.

Extend %OptimizeFunctionOnNextCall with an argument to force OSR to make writing OSR tests easier: %OptimizeFunctionOnNextCall(f, "osr").

R=fschneider@chromium.org
TEST=test/mjsunit/compiler/optimized-for-in.js

Review URL: https://chromiumcodereview.appspot.com/9431030

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10796 ce2b1a6d-e550-0410-aec6-3dcde31c8c00