Runtime_DebugEvaluate creates an empty context which is not correctly handled in FullCodeGenerator::ContextSlotOperandCheckExtensions because the corresponding scope indicates that it has no context.

BUG=crbug.com/107996
TEST=test/mjsunit/regress/regress-crbug-107996.js

Review URL: https://chromiumcodereview.appspot.com/9310027

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10582 ce2b1a6d-e550-0410-aec6-3dcde31c8c00