Fix issue 13474. Simplify graph builder for Boolean operators AND, OR: do not optimize code when the result of the Boolean operator is not used.

R=kmillikin@google.com

Review URL: https://codereview.chromium.org//25630002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@28275 260f80e4-7a28-3924-810f-c04153c831b5
3 files changed