arcade: Helix reporting fails due to non-POSIX compliant line in Helix reporter run

• This issue is blocking
• This issue is causing unreasonable pain

Helix reporting fails due to this line in run.sh not being POSIX compliant and -T not being a valid option on BSD mv (macOS): https://github.com/dotnet/arcade/blob/9131f071c1b48da0f35466e632a212913f21a3f0/src/Microsoft.DotNet.Helix/Sdk/tools/azure-pipelines/reporter/run.sh#L17

The uploading of testResults.xml succeeds, but the test reporting to AzDO fails. Only the Job node shows up as failed.

Example: Agent: dci-mac-build-134 Job : b5c4d0e-515d-4c1b-8382-9f6c2add90b2 Workitem: DiagnosticTests

+ mv -T /Users/helix-runner/.azdo-env-tmp /Users/helix-runner/.azdo-env
mv: illegal option -- T
usage: mv [-f | -i | -n] [-v] source target
       mv [-f | -i | -n] [-v] source ... directory
+ _OLD_PYTHONPATH=
+ export PYTHONPATH=
+ PYTHONPATH=
+ /Users/helix-runner/.azdo-env/bin/python -c 'import azure.devops'
/tmp/helix/working/B65F09CB/p/reporter/run.sh: line 24: /Users/helix-runner/.azdo-env/bin/python: No such file or directory