Fix BuildModules tests

[clcaldwell]

PR Summary

Fixes #1653

Fix failing tests in BuildModules.tests.ps1 .
Move the tests into /Build/ in the central tests dir.
Add a reference to include the new folder path when executing all tests.

PR Checklist

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• Summarized changes
• Change is not breaking
• Make sure all .cs, .ps1 and .psm1 files have the correct copyright header
• Make sure you've added a new test if existing tests do not effectively test the code changed and/or updated documentation
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[JamesWTruher]

thanks for this, this seems to be fine. Interestingly, I wasn't getting any failures on MacOS. Can you let me know which platform was having the problem?