Unittest cleanup made

[AnttiKauppila]

Summary of changes

Unittests cleanup made
CellularDevice still had the old way of defining built time defines and is now removed. Other unittests needed some minor fixes after this.

Impact of changes

Migration actions required

Documentation

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Pull request type

[X] Patch update (Bug fix / Target update / Docs update / Test update / Refactor)
[] Feature update (New feature / Functionality change / New API)
[] Major update (Breaking change E.g. Return code change / API behaviour change)

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Test results

[] No Tests required for this change (E.g docs only update)
[X] Covered by existing mbed-os tests (Greentea or Unittest)
[] Tests / results supplied as part of this PR

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Reviewers

@ARMmbed/mbed-os-wan

[0xc0170]

Please extend the commit msg for Unittest cleanup made, including what is this cleanup (similar to description in the PR here).

[ciarmcom]

@AnttiKauppila, thank you for your changes.
@ARMmbed/mbed-os-ipcore @ARMmbed/mbed-os-wan @ARMmbed/mbed-os-maintainers please review.

[0xc0170]

CI started meanwhile

[AnttiKauppila]

commit msg updated

[mbed-ci]

Test run: SUCCESS

Summary: 1 of 1 test jobs passed
Build number : 1
Build artifacts