Retry failing tests on Safari, because it is flaky.

BUG=dartbug.com/21434

Review URL: https://codereview.chromium.org//691583002

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41397 260f80e4-7a28-3924-810f-c04153c831b5
Try to set any server breakpoint.

R=devoncarew@google.com, brianwilkerson@google.com
BUG=

Review URL: https://codereview.chromium.org//684083003

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge@41398 260f80e4-7a28-3924-810f-c04153c831b5