Shorten --harmony-block-scoping to --harmony-scoping.

R=keuchel@chromium.org
BUG=
TEST=

Review URL: http://codereview.chromium.org/8226017

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9589 ce2b1a6d-e550-0410-aec6-3dcde31c8c00