Functionality test that all transactions on the remote chain roll back if a single one fails

[0xekez]

When submitting a Vec<CosmosMsg> for execution on a remote chain, if any of those messages fail:

1. An error should be returned containing the error for the first message to fail.
2. State changes for all of the other messages should be rolled back.

To do this, I recommend sending a message in the form [hello {}, bank_send {}], where the first call to hello is on the tester contract, and the second sends more tokens than the proxy owns. Execution for the first message should not add a sender (as added in #1), and the callback should return an error about the bank module.

[0xekez]

// If multiple messages are executed, a single one failing should roll
// back all the other messages. This executes three messages:
// ```[good, error1, error2]```
// Good causes a state change. The expected behavior is that an error
// callback is returned containing error1, and the state change is not
// applied.
func TestRollback(t *testing.T) {
}