Fix cpu arch returned value in TestCase.py

[TripleRider]

Modify TestCase.py related to #2159.

Proposed Changes

Replaced platform.processor() with platform.machine() for better cross-platform support. Add amd64 and arm64 as additional supported cpu arch.

Related Work

Issue #2159

PR Checklist

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[TripleRider]

Is there a way to resolve the failing test case. I can't see the proposed changes affecting that particular test case but can look into it if needed.

[jblueh]

@TripleRider This has been an issue before, see #1984. I have also encountered this recently and decided to relax the tolerances further. The fix is pending in #2167.