Switch generator builtins into strict mode.

R=rossberg@chromium.org

Review URL: https://codereview.chromium.org/13985011

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14255 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/generator.js

@@ -25,8 +25,9 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+"use strict";
+
 // This file relies on the fact that the following declarations have been made
-//
 // in runtime.js:
 // var $Function = global.Function;