xFailOverCluster: Opt-in for script files common tests

[johlju]

Pull Request (PR) description

• Changes to xFailOverCluster
  • Opt-in for script files common tests (issue #121).
  • Removed Byte Order Mark (BOM) from the files; CommonResourceHelper.Tests.ps1, MSFT_xCluster.Tests.ps1, MSFT_xClusterDisk.Tests.ps1, MSFT_xClusterPreferredOwner.Tests.ps1.

This Pull Request (PR) fixes the following issues: Fixes #121

Task list:

• [x] Change details added to Unreleased section of CHANGELOG.md?
• [ ] Added/updated documentation, comment-based help and descriptions in .schema.mof files where appropriate?
• [ ] Examples appropriately updated?
• [x] New/changed code adheres to Style Guidelines?
• [x] Unit and (optional) Integration tests created/updated where possible?

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This change is 

[msftclas]

@johlju, Thanks for having already signed the Contribution License Agreement. Your agreement was validated by Microsoft. We will now review your pull request. Thanks, Microsoft Pull Request Bot

[codecov-io]

Codecov Report

Merging #122 into dev will not change coverage. The diff coverage is n/a.

@@        Coverage Diff         @@
##           dev   #122   +/-   ##
==================================
  Coverage   90%    90%           
==================================
  Files        7      7           
  Lines      379    379           
==================================
  Hits       343    343           
  Misses      36     36

[johlju]

Reviewed 6 of 6 files at r1. Review status: all files reviewed at latest revision, all discussions resolved.

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Comments from Reviewable

[johlju]

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Review status: :shipit: all files reviewed at latest revision, all discussions resolved, all commit checks successful.

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Comments from Reviewable