Add a runtimeconfig.json test for WASM

[fanyang-mono]

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

Tagging subscribers to this area: @directhex
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Issue Details

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Author:	fanyang-mono
Assignees:	fanyang-mono
Labels:	area-Infrastructure-mono, untriaged
Milestone:	6.0.0

Tagging subscribers to 'arch-wasm': @lewing
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Issue Details

---

Author:	fanyang-mono
Assignees:	fanyang-mono
Labels:	arch-wasm, area-Infrastructure-mono, untriaged
Milestone:	6.0.0