[BUGFIX] Fix unit tests after latest PHP changes

Latest changes in PHP disallow unserialize on
certain internal classes. Since phpunit uses
unserialize to create objects of such classes
when requesting a mock without calling the constructor
these tests failed with a PHP fatal error.

Instead of skipping the tests, we can simply provide
mocked constructor arguments (if required) so that
phpunit can create a mock object by using the new operator
and passing these mocked constructor arguments.

Change-Id: I26aa06125581b4ca93abcbad2ebb98003509e81a
Resolves: #59979
Related: #59685
Releases: 6.0
[TASK] Improve travis notifications to channels

By default travis notifies on each build when
posting to channels (irc, slack)
We can reduce the number of notifications by only
posting successful builds when it previously failed.
Additionally encrypt the API token for posting to slack.

Releases: 6.3, 6.2, 6.1, 6.0, 4.7, 4.5
Change-Id: I882d34903c972201454e6cc5b9041393e3bd3661