Add tests for *-Computer cmdlets #4146
Description
*-Computer cmdlets need more test coverage.
Related coverage report: https://codecov.io/gh/PowerShell/PowerShell/src/9e41c647a9407e05d86f4971a6bd25719a7130d0/src/Microsoft.PowerShell.Commands.Management/commands/management/Computer.cs
Environment data
> $PSVersionTable
Name Value
---- -----
PSVersion 6.0.0-beta
PSEdition Core
GitCommitId v6.0.0-beta.3
OS Microsoft Windows 10.0.16204
Platform Win32NT
PSCompatibleVersions {1.0, 2.0, 3.0, 4.0...}
PSRemotingProtocolVersion 2.3
SerializationVersion 1.1.0.1
WSManStackVersion 3.0