arm, fix resources mock test

[XiaofeiCao]

the bug will only appear in the second run..

spread is shallow copy, changing in spread model's properties will result in changing in original model's properties use serialize/deserialize instead

Cadl Ranch Contribution Checklist:

• [ ] I have written a scenario spec
• [ ] I have meaningful @scenario names. Someone can look at the list of scenarios and understand what I'm covering.
• [ ] I have written a mock API
• [ ] I have used @scenarioDocs for extra scenario description and to tell people how to pass my mock api check.

[changeset-bot[bot]]

🦋 Changeset detected

Latest commit: b10165057c7219f2ab87543b699838d31a9476e6

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

| Name | Type | | ----------------------------- | ----- | | @azure-tools/cadl-ranch-specs | Patch |

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR