test(multiple): refactor unit tests of several components

[nitinmalave]

Opening this PR as it is required to:

• Refactor variables in various component unit tests to have constant type instead of let as this variables are not getting re-initialize during the test life-time.
• Added type annotations to variables instead of any.
• Renamed variables.
• All tests within a spec should be consistent with all other tests in repo.

[crisbeto]

The changes look good, but the commit title needs to be updated to say test(multiple instead of test(material/multiple).

[nitinmalave]

Fixed it.

[crisbeto]

LGTM

[devversion]

LGTM. Nice work 🎉

[angular-automatic-lock-bot]

This issue has been automatically locked due to inactivity.
Please file a new issue if you are encountering a similar or related problem.

Read more about our automatic conversation locking policy.

_{This action has been performed automatically by a bot.}