consider optional expected calls last.

[rubensayshi]

For a lot of our testsuite we're using mocks as a replacement of some services which in most tests we just want to return something simple and not care too much about them,
except for the tests where we're actually testing if the service is being used properly.

So we had the idea to put some On().Maybe() calls with Anything params on the mocks using the helper which we're already using to build up the various services needed.

However that conflicts with the tests which actually want to mock and assert some method calls themselves because the optional calls are first in the .ExpectedCalls and the more specific calls are never actually reached.

eg;

	var ms1 = new(TestExampleImplementation)
	ms1.On("TheExampleMethod", Anything, Anything, Anything).Maybe().Return(0, nil)
	ms1.On("TheExampleMethod", 1, 2, 3).Return(4, nil)

I think this kinda breaks backwards compatibility, anyone who uses .Maybe() with Anything params and .Times() and has subsequent expected calls could have the methods called in a different other with this change ...