Fix ServiceStateLogicTest

Previously `testManuallySettingIndicatorsOnApplicationsIsMoreComplicated` failed non-deterministically. Though this test name suggested the failure was because it wasn't complicated enough, the actual cause was mostly down to using `assertAttributeEqualsEventually` instead of `assertAttributeEquals` or a couple of wrong assertions `:-)`.

I added some `assertAttributeEqualsContinually` assertions for when we expect the state to remain the same after changing some other attribute or config. This is because the test failed non-deterministically (which could be made deterministic with some `sleep(1000)` added temporarily.

I renamed the test to `testManuallySettingIndicatorsOnApplications`. Longer term, it might well be worth splitting this big test into multiple small tests that each test a smaller number of cases.
Why not put this (and surrounding assertions not added in this PR) into `brooklyn.test.Asserts` as they all seem generic enough to be useful elsewhere?