Replace assertTrue/False with assertEqual/NotEqual

The following replacements were done in tests to have
clearer messages in case of failure:
- assertTrue(* == *) with assertEqual
- assertTrue(* != *) with assertNotEqual
- assertFalse(* == *) with assertNotEqual

Change-Id: Idbb1a292cf8545b87728fa2b815c67f923ef6efa
Merge "Replace assertTrue/False with assertEqual/NotEqual"