Tests that DOM Mutation Observers do not attempt to deliver mutation records while the debugger is paused.Bug 105810

DIV and observer setup.
deliveryCount = 0
setAttribute should have triggered delivery.
deliveryCount = 1
mutateAndPause invoked.
Script execution paused.
Delivery should not have taken place.
deliveryCount = 1
Script execution resumed.
Second delivery should now have happened.
deliveryCount = 2